Scale in Vineyards Identification and Control FINAL REPORT to SA Central, Wine Australia Regional Program Principal Investigator: Ms Jenny Venus Principal Investigator: Ms Jenny Venus Date: 31 July 2017 1
Table of Contents FINAL REPORT to SA Central, Wine Australia Regional Program... 1 AUSTRALIAN GRAPE AND WINE AUTHORITY... 1 1. Abstract... 3 2. Background:... 3 3. Project aims... 4 4. Project Timeline... 5 5. Trial 1: Year 1 (2014/15)... 5 Materials and Methods... 5 Treatments... 6 Trial Layout... 6 Assessment... 6 Results... 8 Discussion... 8 6. Trial 2: Year 1 (2014/15)... 9 Sooty Mould Control... 9 Treatment:... 9 Results...10 Identification of sooty mould...11 Conclusions from trial work in year 1 (2014-15):...11 7. Trial 3: Year 2 (2015/16)...11 Scale control and identification...11 Project...11 Materials and Methods...11 Drip applied product...12 Foliar applied products...12 Products and application time...12 Results:...12 Discussion...15 8. Trial 4: Year 3 (2016/17) Demonstration sites...16 Material and Methods...16 Results...16 Discussion:...17 9. Identification and lifecycle of scale...18 Identification...19 10. Summary...20 11. Dissemination of information...21 12. Ongoing research...21 13. References...22 14. Acknowledgements...22 Appendix 1: Weather data 2014-2017...23 Appendix 2: Raw data for Trial 1...25 2
1. Abstract Scale insect numbers have increased in vineyards throughout South Australian over the last 10 years. Scale are a soft body insect that feed predominately on phloem cells (Simbiken etal 2015). Phloem sap is rich in carbohydrates but poor in soluble nitrogen compounds, therefore the scale insects must ingest large quantities of sap to meet their nutritional requirements. The excess carbohydrate rich solution is commonly referred to as honeydew (Malumphy 1997). Ants are attracted to the honeydew and it is also a substrate for sooty mould. Sooty mould can reduce the photosynthetic rate of the leaf, traps heat from sunlight, and reduces the value of the fruit. The feeding by soft scale removes nutrients and carbohydrates from the plant, which slows plant growth and causes some necrosis that may lead to dieback of canes and spurs (Rakimov etal 2015). Overall, scale have an impact on both vine vigour and fruit quality. The dominant scale observed throughout the three years of research were the Grapevine scale (Parthenolecanium persicae), and Frosted scale (Parthenolecanium near pruinosum). Both Frosted and Grapevine scale are reported (Rakimov etal 2015) to have only one generation per year. However, it was observed that in South Australia there can be either more than one lifecycle per season or the scale are not all maturing at the same time, and hence many different instars may be present at the one time. Prior to the commencement of this project the impact soft scale insects were having on vine health and fruit quality was poorly understood. Furthermore, there were very few effective control measures for scale. The wine grape Industry now has a better understanding of the impact scale are having on the vineyards and fruit quality across South Eastern Australia and there are some strategies in place to assist growers to control scale in their vineyards. 2. Background: Scale insect were first noted as having an impact on vineyard health in Langhorne Creek in the 2011 vintage. High levels of sooty mould were observed on leaves of shiraz and merlot grape varieties and was found to be related to scale insects. Up until that time scale insects had not caused any significant problems in vineyards across Langhorne Creek. Scale was monitored for the following three vintages (2012, 2013 and 2014) and in 2014 vineyards in the Langhorne Creek region had levels of sooty mould that where above acceptable levels for the wineries purchasing the fruit. The presence of soft scales in vineyards is not obvious to many grape growers because of their small size and inconspicuous habits. The dead mature scales from the previous season and overwintering juvenile scales are most obvious after leaf fall in winter. Scale numbers are often underestimated because juvenile scales overwinter on the underside of canes or spurs, and underneath bark on the trunk or cordon of the vines. The identification of different species is difficult during winter as the immature stages of grapevine scale, frosted scale and soft brown scale are very similar (Buchanan 2008). The presence of ants and sooty mould on leaves and fruit is often what growers first notice in the vineyard. On closer inspection, it is often found that the ants are farming the scale for honeydew. Over the past three years it has become apparent that soft scales are common and often abundant pests in many Southern Australian vineyards. In many vineyards, there were mixed infestations of grapevine scale with frosted scale, the other scale such as soft brown scale and nigra scale where not observed in any vineyards that where inspected over the three-year time frame of this project. 3
Throughout the three-year trial beneficial insects such as parasitic wasps (Metaphycus maculipennis), predatory lacewings and ladybirds appeared to have very little impact on the large populations of scale. Buchanan (2008) noted that frosted scale do not have any effective parasitoids in Australia, while the grapevine scale is thought to be mainly controlled by the parasitic wasp. It was observed that scale not only produce honeydew that is than colonised by black sooty moulds causing fruit to be downgraded or rejected, but also causes delayed budburst (photo 1), can weaken canes and reduce the photosynthetic capacity of leaves. PHOTO 1: LEFT SIDE SCALE CONTROLLED WITH CLOTHIANIDIN, RIGHT HAND SIDE CONTROL ROW DELAYED BUDBURST. Currently there are very few control methods for scale. The winter oil sprays are often ineffective due to the scale harbouring under the bark (photo 2) where it is difficult to get the oil in contact with the scale. PHOTO 2: JUVENILE SCALE (NYMPHS) HARBOURING UNDER BARK THROUGH-OUT WINTER. Three years of trial work has now been completed looking at the impact of scale on vineyard health and the effective control methods. 3. Project aims The specific aims of the project: 1. Identify the scale species that are present in vineyards in the central wine regions of South Australia. 2. Trial a variety of chemical control options to develop a recommendation for growers. 3. Make observations in relation to the impact of beneficial insects on the control of scale insects. 4
4. Disseminate information to growers about how to identify scale and the impact of scale on vineyards. 4. Project Timeline Year Project Outcome Year 1 (2014-15) Trial new control methods Limited success due to high population of scale in the trail sites. Year 2 (2015-16) Investigate impact of scale on vine health. On farm trial of control options Poster presentation AWITC 2016 Significant impact on spur health and budburst. Successful control with Clothianidin. Poster presented at AWITC Year 3 (2016-17) Replicate on-farm trial Residue found in some fruit after Clothianidin application Identification of scale species Dissemination of trial information. Predominately Grapevine Scale and Frosted Scale Webinar, grower talks and report. 5. Trial 1: Year 1 (2014/15) Identify effective control methods for all the scale species present in vineyards in the Langhorne Creek region. Materials and Methods The conventional method of scale control is with a winter oil or a paraffinic oil spray in winter after pruning when the vines are dormant. Pesticide oil sprays control scale through suffocation, oils can also impact on the feeding and egg laying behaviour of scale. It is recommended that oil sprays coincide with the presence of the young, recently hatched stages (crawlers). This is difficult to achieve in vines as the crawlers don t hatch until flowering. The other problem with oil sprays in vineyards is that the 2nd and 3rd instars are well protected under the bark (see photo 2), making it very difficult to achieve suffocation. The products chosen for the trial were either registered for scale or mealybug, but not commonly used for that purpose. Only products that were registered with the APVMA (Australian Pesticides and Veterinary Medicines Authority) were included in the initial trial work. Two trial sites where established in Langhorne Creek, one north and one south of the township. Four products were chosen as potential options for controlling scale. A control spray of water was also included in the trial. Products where applied at a dilute rate of 1000L/ha water and all products were applied at the label rate. If an adjuvant was recommended on the label it was included in the spray mix. 5
Products were applied using a spray unit mounted on a 4-wheeled motorbike. Each treatment area was marked out as per Table 1 and 2. Table 3 is the colour code grid for the products. Treatments (Registered Trade names and active chemical constituent names indicated for each) Movento (Spirotetramat 240 g/l) @ 40ml/100L + Agridex ** (Paraffinic petroleum oil 715 g/l + Polyol fatty acid esters/emulsifier 139 g/l) @ 50 ml/100 L of spray mixture. ** Agridex was used in place of Hasten (recommended on label) as Hasten was not declared GMO free at the time of the trial. Applaud (440 g/l Buprofezin) @ 60 ml/100l Biopest (815 g/l Paraffinic oil) @ 1L/100L (used at the powdery mildew rate as sprayed in season not as a dormancy spray). Transform WG (500 g/kg Sulfoxaflor) @15g/100L Untreated Control: water only Trial Layout Site 1 - North Riesling 2.5m Row X 1.8m vine spacing. One panel per treatment 4 vines per panel. Treatment date: 14 th November 2014. Growth Stage EL 25 TABLE 1: SITE 1 - NORTH Panel Row 72 Row 73 1 Blank Blank 2 Blank Blank 3 Green Orange 4 Pink Green 5 White Pink 6 Orange White 7 Blue Blue 8 Pink White 9 Green Orange 10 Orange Pink 11 White Blue 12 Blue Green 13 Blank Blank Site 2 - South Cabernet: 2.5m Row X 1.8m vine spacing One panel per treatment, 4 vines per panel. Treatment date: 15 th November 2014. Growth Stage EL 19 TABLE 2: SITE 2 SOUTH Panel Row 81 Rep 1 Row 82 Rep 2 Row 830 Rep 3 Row 84 Rep 4 1-4 Blank Blank Blank Blank 5 Green Pink Blue Orange 6 Blue Blue Pink Blue 7 Orange White Green White 8 Pink Green Orange Pink 9 White Orange White Green 10 Blank Blank Blank Blank TABLE 3: PRODUCT COLOUR CODING Movento Applaud Bio-pest Transform WG Water control Blue Green Pink Orange White Assessment The scale numbers were initially very high at both sites. Scale were a mix of Frosted and Grapevine scale at Site 1 and predominately Grapevine scale at Site 2. Scale were observed to be hatching from the 28 th October through to the 7 th November 2014. Products were applied on the 15 th November to coincide with the crawlers emerging from under the protective cover of the dead mature females (Photo 3). 6
PHOTO 3: SCALE EGGS HATCHING, CRAWLERS MOVING ONTO BASAL LEAVES Ten basal leaves per panel (treated area) were sampled in the first week of each month throughout the growing season (November through to March). Basal leaves were randomly selected and placed in a labelled paper bag. The ten samples were than put into a plastic bag and stored in a chilled esky. The leaves were assessed within 48 hours of collection. A 7cm disc was used to outline the assessment area on each leaf. This was to eliminate the variability in scale number due to leaf size. The scale were counted using a X20 microscope (Photo 5). Only the final results are reported as it was very difficult to assess if the scale where dead or alive in the initial assessments. PHOTO 4: NYMPHS ON THE UNDERSIDE OF A LEAF. At the start of the trial there were high numbers of scale present at both sites, hence the reason these two sites were chosen for the trial. The average number of scale per leaf at the north site was recorded as 63 per 7cm disc. It should be noted that once the number was above 150 scales, the scale number was recorded as 150. Similarly, at the southern site, the average number of scale per leaf disc (7cm) was 57, however once the scale number was over one hundred the number of scale was recorded as maximum of 100 rather than 150 as per the northern site. There were instances when the number of scale per 7cm leaf disc was well over 100 however only 100 scale nymphs where recorded. The method of recording a maximum of either 150 or 100 nymph scales per leaf was to reduce the time taken to count each leaf sample as 200 samples needed to be counted every time the trial was sampled. The counting was done using a microscope as it was often difficult to see the scale on the underside of the leaves. Scale often hid under the leaf veins, or were very close together. Photo 5 shows the scale under magnification, it is much easier to see the scale in Photo 5 compared to Photo 4. Photo 6 shows the number of scale on the shoot, often scale insects are also on the leaf petiole. These were not included in the count, only scale on the leaf, inside the 7cm disc were counted. 7
PHOTO 5: SCALE UNDER X20 MAGNIFICATION PHOTO 6: SCALE ON PETIOLES AND STEMS. Results The results have been tabulated and raw data is available in Appendix 2. TABLE 4: SITE 1 - NORTH Treatment Colour Code Percent Control Average number scale per Movento Blue 29% 43 Applaud Green 16% 48 Bio-pest Pink 10% 58 Transform WG Orange 28% 45 Control - Water White -1% 65 treatment TABLE 5: SITE 2 SOUTH Treatment Colour Code Percent Control Average number scale per treatment Movento Blue 25% 44 Applaud Green 18% 48 Bio-pest Pink 6% 60 Transform WG Orange 27% 37 Control - Water White -2% 59 Discussion Transform WG and Movento where the best products in the trial. This was most likely due to the mode of action of these chemicals, being systemic rather than contact in nature. Both Transform WG and Movento are xylem and phloem mobile, therefore they are not reliant on good coverage to control the scale. The products have a residual presence of approximately 3 weeks hence if the scales are hatching over a longer period the residual effect will still have an impact of the later hatching scale. In comparison, Applaud and Bio-pest are contact products, they need contact with the scale for the products to be effective. The contact insecticides generally work best on the 1 st instar or crawlers as they only have a thin layer of naturally occurring protective wax. The high number of scale present at the trial site meant the 29% reduction in scale numbers to an average of 43 scale per leaf was still not enough to improve the vine health or eliminate sooty mould. 8
6. Trial 2: Year 1 (2014/15) Sooty Mould Control Due to the high level of sooty mould on fruit through vintage 2015 (Photo 7) and the issue of fruit being rejected due to the impact of the sooty mould on fruit quality, a trial was set up to see if sooty mould could be washed-off or if the level of sooty mould could be reduced to less than 2% (rejection level of most major wine companies). PHOTO 7: HONEYDEW AND SOOTY MOULD ON SHIRAZ FRUIT AT HARVEST. Treatment: A one metre by one metre section of Shiraz was treated with each product. The products were applied using a hand-held spray pack sprayed to the point of run-off (assessed inside the canopy). The canopy was a sprawled canopy with one foliage wire. It was determined that the equivalent of 1200L/ha water was required to completely wet the 1m x 1m section. Four applications of each product were applied as per the layout in Table 6 1. Vinegar 2. Naturasoap (430 g/l fatty acid potassium salts) 3. Scale gun (20g/L Petroleum Oil, 0.3g/L Pyrethrins, 1.2g/L Piperonyl Butoxide) 4. Eco-pest (19.46g/L Paraffin Oil) 5. Eco-oil (8.5 g/l Emulsifiable Botanical Oil) 6. Eco-fungicide (940 g/kg Potassium Bicarbonate) 7. Control (water) PHOTO 8: EXAMPLE OF NATURASOAP TRIAL SITE 9
TABLE 6: SOOTY MOULD TRIAL LAYOUT: Panel Row Row 1 Blank Blank 2a 2 3 2b 4 1 2c 3 5 2d 6 4 3a 5 6 3b 7 2 3c 1 7 3d 3 4 4a 5 6 4b 1 7 4c 4 2 4d 7 5 5a 6 1 5b 2 3 5c Blank Blank 5d Blank Blank PHOTO 9: ECO-FUNGICIDE TREATED BUNCH ON RIGHT AND BELOW. PHOTO 10: DROP OF VINEGAR NEXT TO SCALE NYMPH Results There was no impact on the level of sooty mould with any of the products trialled. Photo 9 shows the effect the Eco-fungicide had on the sooty mould. It did appear to reduce the level of sooty mould however the skin of the fruit still had a black residue remaining on the surface of the fruit. Photo 10: gives an indication of how difficult it is to contact the scale with spray. An assessment of the impact of the products on scale viability was also undertaken, however there was no significant difference between the treatments and the control. It was determined that it is very difficult to wash of the sooty mould particularly in a sprawled canopy. 10
Identification of sooty mould Sooty moulds are a remarkable, but poorly understood group of fungi. They coat fruits and leaves superficially with black mycelia which reduces photosynthesis rates of host plants (Chomnunti etal, 2014). Sooty mould is commonly thought to comprise mainly of Capnodiales fungi (Barbara. Hall, pers. Comm., 2016). Samples of sooty mould infected leaves were sent to Dr Michael Priest (Department of Primary Industry (DPI), Orange). Dr Priest concluded that the organism causing the black mould was not from the fungal group Capnodiales but rather a mix of fungi including Aureobasidium, Cladosporium, Acremonium, Trichothecium roseum and other fungi of unidentifiable morphologically. Therefore, potentially whatever is naturally present in the subject vineyards. Conclusions from trial work in year 1 (2014-15): On completion of the two trials it was determine that growers should try and control the scale rather than leaving the scale un-checked and trying to wash off the sooty mould pre-harvest. The products used in Trial 1 did have an impact on the scale, however the numbers where not reduced enough to be able to conclude that any of them were a successful control method. A recommendation for growers was not formulated at the end of year one due to the low control rates of the products. It was determined that a product would need to control 70% or more of the scale before it would be recommended to growers. Due to the increasing pressure from the grape growing industry the trial was expanded in year 2 to included insecticide treatments in winter and to continue the trial of Applaud and Movento during the growing season. Transform was removed from the trial at the request of wineries. Rather than small panel trials the second year of trialling was conducted in a commercial way, where products were applied using the growers spray cart and entire blocks where treated with 5 rows left untreated as a control. 7. Trial 3: Year 2 (2015/16) Scale control and identification Throughout the 2015 vintage the level of sooty mould on fruit was noticeable and the products trialled in November 2014 had not controlled enough scale to reduce the sooty mould levels at vintage. Growers where very concerned about the level of sooty mould and the impact it was having on fruit quality. Products that could control a wider spectrum of scale growth stages were included in the second year of the trial. The trials where conducted on whole blocks rather than panels to reflect the commercial aspect of scale control. Project Identify effective control methods for all the scale species present in vineyards in the Langhorne Creek region. Materials and Methods Foliar and drip applied treatments were trialled as outlined below. TABLE 7: SAMURAI TRIAL SITES 2015-16 Block Variety Region Growth Stage 1 Chardonnay Adelaide Hills EL10 2 Pinot Noir Adelaide Hills EL10 3 Chardonnay Langhorne Creek EL10 4 Shiraz Langhorne Creek EL10 5 Shiraz Langhorne Creek EL10 6 Shiraz Langhorne Creek EL10 7 Riesling Langhorne Creek EL10 11
Drip applied product Drip application of Samurai (Clothianidin). Seven blocks where treated across the Adelaide Hills and Langhorne Creek (Table 7). Within each block, five rows of drip irrigation line had taps installed to allow for those rows to be turned off when the Samurai was applied. The Samurai was applied to the whole block via injection at the valve. To reduce the impact of Samurai on the bee population, all the treated blocks were sprayed under vine with an herbicide prior to the Samurai application. This was to ensure there were not any weeds that would take up the Samurai and attract or expose bees to them when flowering. The mid rows were slashed to remove any flowers to reduce the number of bees moving into the block and foraging on midrow flowers. The blocks where irrigated prior to the Samurai application. The block was irrigated for one hour prior to the injection of the Samurai. The Samurai was injected into the irrigation system and then the block was irrigated for another 4 hours to flush the product into the soil profile. Leaf samples were taken one month and three months after the application and tested for levels of clothianidin. This was to ensure the product was in the leaf. Scale were monitored using a similar technique as used in year 1. Due to the whole block being treated rather than leaves being collected from individual panels, thirty (30) leaves per treatment were collected and assessed. Foliar applied products Selected growers across Langhorne Creek, Adelaide Hills, as well as the Barossa applied a single product to a block and left 5 rows unsprayed as a control. The products were applied in a commercial manner using the growers spray cart and water rates. All products where applied at the label rate. An adjuvant was only added if the label recommended a wetter. Products and application time TABLE 8: TRIAL LAYOUT FOR FOLIAR APPLIED PRODUCTS Product Variety Region Timing Movento + Agridex Chardonnay Riesling Cabernet Adelaide Hills Langhorne Creek Barossa EL18 Applaud Stifle (Winter Oil) Lorsban (Chlopyrifos) Cabernet Riesling Chardonnay Chardonnay Shiraz Shiraz Chardonnay Chardonnay Langhorne Creek Langhorne Creek Riverland Adelaide Hills Langhorne Creek Langhorne Creek Langhorne Creek Adelaide Hills EL 23 Dormant Spray 3 weeks before bud-burst Dormant Spray 3 weeks before bud-burst As mentioned previously, Transform was removed from the trial as the request of wineries and the list of treatments was devised in consultation with the industry. Results: Part of the protocol for the trial was to sample leaves and test for the level of clothianidin residue. This was to ensure that the clothianidin had moved into the vine and that the scale death that was being observed in the trial sections treated with Samurai could therefore be attributed to the Clothianidin 12
rather than another factor. The blocks that had product applied via a spray cart did not have leaves tested for residue as there was no doubt that the products had been applied to the canopies. The leaf samples were sent to the Australian Wine Research Institute (AWRI) for residue testing. In the initial protocol only leaf samples were to be tested, however some fruit samples where tested at the request of a winery that was taking some of the fruit. The leaf and fruit residue levels are presented in Table 9. In most blocks, the level of Clothianidin in the leaf peaked in December or January and had declined to close to the limit of detection (LOD: 0.05 mg/kg for marc) by March 2016. It was not anticipated that fruit residues would be detected as none were detected when the product was registered by Sumitomo with the APVMA. Comments reported in the Trade Advice Note on Clothianidin in the product Sumitomo Samurai Systemic Insecticide (APVMA Product Number 60687) APVMA: The proposed rate for soil application to both wine and table grapes is a maximum of one application at 600g / planted hectare ( 300g a.i./planted hectare) between budburst and the end of flowering. The applicant states that soil application is made early in the grape vine growth stage (typically before the pre-flowering stage). Trial data from four Australian trials shows that after one soil application at 300g a.i./sprayed hectare (i.e. 1x the proposed application rate for soil application) to either wine or table grapes and a PHI of 96-132 days, no detectable residues were found. In addition, in the trial in which a 96 day PHI was observed, no residues were observed after a single application at a rate of 600g a.i./ha. It is considered that the residue trials adequately address the proposed GAP. It is appropriate that an MRL be established for wine grapes of *0.02 mg/kg. Residues are unlikely to be significant in wine as residues in wine grapes (after soil application of clothianidin) are below the level of detection (0.01 mg/kg). The potential risk to trade through the export of wine or any commodity from processed wine grapes is therefore considered to be low. Residue was detected in four of the fruit samples that were tested. The Grenache block was retested two months after the initial test and the residue had declined to below 0.01mg/kg. Because a residue was not acceptable there was some concern about the accuracy of testing hence a sample was split and sent in twice (ie Sample 2 and 4 are from the same fruit sample) and a sample was split between the AWRI and a laboratory in Sydney (Sample 3 Chardonnay). There was 0.01 mg/kg difference between Sample 2 and 4 and between the sample that was sent to two different laboratories. Alarm was not raised about the residue as it was thought that there may have been a mistake in application or sampling was causing the residue. However, due to the residue being detected, Samurai was not released to growers for general use for the control of scale, rather a third year of trialling was put in place to monitor the residue in fruit when blocks were treated with Clothianidin. Table 10 outlines the results for the Samurai, Chlorpyrifos, Movento, Applaud and mineral oil trial. 13
TABLE 9: SAMURAI (CLOTHIANIDIN) LEAF AND FRUIT RESIDUE RESULTS Location Sample Description Sample DATE Clothianidin mg/kg LC T1 Shiraz R1107-1133 Control Leaf 1/12/2015 <0.05 LC T1 Shiraz R1107-1133 Control Leaf 8/01/2016 <0.05 LC T1 Shiraz R1128-1132 Samurai Treated Leaf 1/12/2015 0.12 LC T1 Shiraz R1128-1132 Samurai Treated Leaf 8/01/2016 0.18 LC T1 Shiraz R1128-1132 Samurai Treated Leaf 4/03/2016 0.05 LC T2 Cabernet R140-141 Treated Leaf 8/01/2016 0.07 LC T2 Cabernet R140-141 Treated Leaf 4/03/2016 <0.05 LC T2 Cabernet R147-148 Control Leaf 8/01/2016 <0.05 LC T3 Shiraz R431-435 Leaf 4/03/2016 0.06 LC T4 Cabernet R109-113 Treated Leaf 1/12/2015 0.16 LC T4 Cabernet R109-113 Treated Leaf 4/03/2016 <0.05 LC T5 Shiraz R45-46 Treated Leaf 4/03/2016 <0.05 LC T6 Shiraz R110-111 Treated Leaf 1/12/2015 0.13 LC T6 Shiraz R110-111 Treated Leaf 4/03/2016 <0.05 LC T6 Shiraz R133-134 Control Leaf 1/12/2015 <0.05 LC T7 Merlot R131-132 Control Leaf 1/12/2015 <0.05 LC T7 Merlot R150-151 Treated Leaf 1/12/2015 0.24 LC T7 Merlot R150-151 Treated Leaf 4/03/2016 0.06 LC T8 Alternative Variety Control Leaf 8/01/2016 <0.05 LC T8 Alternative Variety R25-26 Treated Leaf 8/01/2016 0.31 LC T8 Alternative Variety R25-26 Treated Leaf 4/03/2016 0.06 MV MV Shiraz Fruit 12/02/2016 <0.01 LC Pinot Fruit 6/04/2016 <0.01 LC Riesling Samurai Treated Fruit 12/02/2016 <0.01 BAR Grenache Control Leaf 8/01/2016 <0.05 BAR Grenache TMT R225-6 Leaf 8/01/2016 0.02-0.03 BAR Grenache TMT R225-6 Fruit 12/02/2016 0.02 BAR Grenache TMT R225-6 Fruit 20/04/2013 <0.01 Adel Hills Blk 26 Chardonnay Fruit 8/03/2016 <0.01 Adel Hills House Pinot Treated Fruit 8/03/2016 <0.01 Adel Hills Pinot TMT R25/26 Fruit 12/02/2016 <0.01 Adel Hills Top Pinot Treated Fruit 8/03/2016 <0.01 LC Sample 1 Cabernet Fruit 11/03/2016 0.01 LC Sample 2 Fruit 11/03/2016 0.03 LC Sample 3 - Chardonnay Fruit 11/03/2016 0.02 LC Sample 4 repeat of Sample 2 Fruit 11/03/2016 0.02 LC Pinot Noir - Late application Samurai applied in April Leaf 3/05/2016 0.12 Sample VARIETY tested at Sydney Laboratory Date Result mg/kg AH Sample 3 - Chardonnay Fruit 8/03/2016 0.01 14
TABLE 10: SUMMARY OF RESULTS FROM FOLIAR AND SOIL APPLIED PRODUCTS. Site Variety Region Treatment Scale Number on treated leaves (average) Scale Number on control leaves (Average) Percent Control Average over treated sites Site 5 Chardonnay Adelaide Hills Stifle Oil 15.00 23.93 37% Site 13 Shiraz Langhorne Creek Stifle Oil 66.80 89.87 26% 31% Site 11 Shiraz Langhorne Creek Lorsban 28.33 85.77 67% Site 8 Chardonnay Langhorne Creek Lorsban 19.77 64.87 70% Site 4 Chardonnay Adelaide Hills Lorsban 5.13 23.73 78% 72% Site 2 Chardonnay Adelaide Hills Movento 19.43 32.63 40% Site 18 Riesling Langhorne Creek Movento 29.80 54.50 45% Site 6 Cabernet Barossa Movento 2.53 68.70 96% 61% Site 1 Chardonnay Adelaide Hills Samurai 0.77 34.10 98% Site 3 Pinot noir Adelaide Hills Samurai 3.40 60.60 94% Site 7 Chardonnay Langhorne Creek Samurai 2.00 64.87 97% Site 9 Shiraz Langhorne Creek Samurai 3.10 75.03 96% Site 10 Shiraz Langhorne Creek Samurai 3.53 85.77 96% Site 12 Shiraz Langhorne Creek Samurai 1.60 85.00 98% Site 14 Riesling Langhorne Creek Samurai 3.70 92.27 96% 96% Site 15 Cabernet Langhorne Creek Applaud 34.30 52.33 34% Site 16 Riesling Langhorne Creek Applaud 48.60 61.33 21% Site 17 Chardonnay Riverland Applaud 23.30 32.40 28% 28% Discussion The commercial application of Clothianidin controlled 96% of the population over 7 sites. Chlorpryifos also had a high control rate of 72%. Similar results were published by CCW (Cotsaris etal 2009), where they found oil alone controlled 44% of soft scale, while oil + chlorpyrifos controlled 99%. The results from this trial were not as high those in the CCW trial. This may be due to a different mix of species in the Riverland (where the CCW trial was conducted) compare to the southern parts of South Australia. Movento worked very well in the Barossa (96% control) however when averaged out with the trial sites in the Adelaide Hills the overall control was only 61%. The difference in control between the Adelaide Hills and the Barossa may be due to the temperature variation between the two sites. The scale hatched earlier in the Barossa. Therefore, when the product was applied more crawlers were out on leaves feeding. Due to the cooler weather in the hills the hatching occurred over a longer period hence less crawlers were visible when the Movento was applied. The oil and Applaud, both contact insecticides, had low control rates of 31% and 28% respectively. This was most likely due to several factors. Firstly, not all the scale had hatched when the Applaud was applied. Applaud inhibits the synthesis of chitin by suppressing the hormone that regulates the process in the insects. Applaud is absorbed by the insect either through direct contact or by ingestion. Both rely on good coverage of the crop and scale. Furthermore, timing spray application to target crawlers is very 15
important as the crawlers are the most susceptible growth stage of the scale lifecycle (Dow Agrosciences: Applaud Insecticide Technical Manual). At the time of application (EL25) the canopy was quite dense and it was difficult to achieve good coverage inside the canopy where the scale insects were harbouring. As mentioned previously, not all the scale had hatched and Applaud does not effect mature females or eggs. Similarly, the dormant oil spray needs to contact the juvenile scale. As shown in year 1, the juvenile scale insects are hidden under the bark and well protected from an oil spray. 8. Trial 4: Year 3 (2016/17) Demonstration sites Repeat year 2 trial to ensure results were repeatable and reliable. Monitoring of the Clothianidin residue in fruit when Samurai is used on a commercial area. Material and Methods Year 3 focused on the Clothianidin application rates and timing, and residue concerns. Entire blocks in Langhorne Creek, Adelaide Hills, as well as the Barossa were treated with label rates of Samurai. The application requirements were the same as in year 2 i.e. the under vine area was sprayed out with an herbicide and the midrow was slashed prior to application. The product was applied via the drip line and watered in. Two blocks in Langhorne Creek and one block in the Adelaide Hills, Barossa and McLaren Vale where monitored. Fruit samples were collected approximately 3 weeks prior to harvest and sent to the AWRI (Adelaide) where a multi residue test was carried out. Results All blocks treated with Samurai, irrespective of variety, had above 90% control of scale. The level of scale control was similar to that found in the previous year, proving that Clothianidin can be successfully used to control scale (regardless of species). ( The first samples for residue testing were sent to the AWRI in March and two of these recorded a detectable clothianidin residue. In response to the positive result the number of blocks to be tested was increased and some blocks were tested multiple times to make sure the results were true and repeatable positive results. Table 11 gives a summary of all the residue testing carried out in the 2017 vintage. PHOTOS 11 & 12: IMPACT OF SCALE ON BUDBURST. FIVE ROWS OF CONTROL STILL INFESTED WITH SCALE. VINES WITH GREEN TIPS TREATED WITH SAMURAI IN PREVIOUS SEASON. 16
TABLE 11: SAMURAI (CLOTHIANIDIN) RESIDUE RESULTS. Region Variety Treatment Time Rate Sampling Date Clothianidin Residue in Leaf mg/kg Clothianidin Fruit Residue mg/kg Name No + / - Langhorne Creek Shiraz Early October 800g/ha 17/03/2017 0.03 Sample A 1 + Langhorne Creek Shiraz Early October 800g/ha 31/03/2017 0.05 Sample A 1 + Langhorne Creek Shiraz Early October 800g/ha 17/03/2017 0.02 Sample B 2 + Langhorne Creek Shiraz - North Late September 800g/ha 31/03/2017 0.03 Sample B 2 + Langhorne Creek Shiraz - South Late September 800g/ha 31/03/2017 0.02 Sample B 2 + Langhorne Creek Shiraz (treated late) April 3200g/ha 19/04/2017 0.03 Sample B 2 + McLaren Vale Grenache - NR Late September 800g/ha 17/03/2017 <0.05 0.02 Sample C 3 + McLaren Vale Grenache - NR Late September 800g/ha 19/04/2017 <0.05 0.02 Sample C 3 + Langhorne Creek Chardonnay Late September 800g/ha 17/03/2017 0.09 0.02 Sample D 4 + McLaren Vale Shiraz (Mulched) Late September 800g/ha 17/03/2017 0.08 0.01 McLaren Vale Shiraz (No Mulched) Late September 800g/ha 17/03/2017 <0.05 <0.01 Sample E - Mulch 5 + Sample E - No Mulch 5 nil Langhorne Creek Grenache Early October 800g/ha 17/03/2017 0.03 Sample F 6 + McLaren Vale Cabernet Late September 800g/ha 17/03/2017 <0.01 Sample G 7 nil Langhorne Creek Sauv Blanc Early October 800g/ha 17/03/2017 <0.01 Sample H 8 nil Adelaide Hills Pinot Gris Early October 800g/ha 31/03/2017 <0.01 Sample I 9 nil McLaren Vale Grenache - RR Late September 800g/ha 19/04/2017 <0.01 Sample J 10 nil Langhorne Creek Shiraz Early October 800g/ha 31/03/2017 0.05 Sample K 11 + MRL for Winegrapes 0.02 Percent of samples that tested +ve 63% Discussion: The trial conducted in 2016-17 confirmed that Clothianidin does move into the grape berries and is detected as a residue at vintage. Of the 11 samples submitted 7 recorded a residue greater than the LOD of <0.01 mg/kg. The Australian MRL for Clothianidin is 0.02 mg/kg in wine, however many of the wine companies strive for nil detection of all agrochemicals used in the growing of wine grapes. Very little is known about the fate of Clothianidin through the wine making process because residues where not detected at the time the product was registered, and therefore winemaking and the tracking of the chemical through the winemaking process was not required. As in previous seasons, Clothianidin gave excellent control of scale and the vine health improved once the scale insects were no longer infesting the vines. Due to the number of samples detected with residues an additional year of trialling will be carried out to determine the fate of clothianidin through winemaking. Even though Samurai is registered for the control of mealybug in wine grapes it is highly recommended the product not be used until the fate of the chemical through winemaking is fully understood. 17
9. Identification and lifecycle of scale Soft scale insects are largely female, not requiring a male to reproduce. The scales studied in this project are readily visible to the naked eye from about 2mm in size. The adults range from 5-7mm in length. The lifecycle of soft scale insects is greatly impacted by the environment (temperature and humidity). In brief, the female life cycle consists of an egg phase, two or three nymphal instars and the adult phase (Photo 11). The first instar or crawlers are very mobile and are dispersed by crawling away from their mothers or passively through wind movement. According to literature (Yardeni etal 1987) wind can carry crawlers 55m to >4km. Once the first instar has migrated or blown to a feeding site (generally the underside of a basal leaf), they remain at the feeding site until the end of the growing season. The second instars look very similar to the first instars, but are slightly larger and depending on species can be darker in colour. Some species including the Grapevine scale develop through to a third instar. Frosted scale only has 2 instars before developing into a mature female. Most scale overwinter as either the second or third instar. When the vine leaves begin to senesce, the scale migrate back to the spurs and main cordon where they seek protection under bark for winter. The scale rapidly grows in spring to mature into a female confined under a protective outer shell. The female then lays between 100 2000 eggs depending on the species (Camacho etal, 2015). 8 1 2 7 Scale Life cycle. 1. Eggs under mature female 2. Crawlers emerging 3. Crawlers migrating to leaves 4. 2 nd instar / nymphs on basal leaf 5. 2 nd or 3 rd Instar over wintering on spurs 6. Female growing rapidly in spring 7. Mature females 8. Eggs visible under mature female. 3 6 5 4 PHOTO 11: LIFECYCLE OF SCALE IN LANGHORNE CREEK 18
Most scale are univoltine, they only have one life cycle per year (Simbiken etal. 2015). However, in warmer climates they can become bivoltine or multivoltine and have several generations per season (Photo 12). In Langhorne Creek, females where maturing in February and laying eggs indicating that the scale were bivoltine. Photo 12: Scale maturing in March and April Identification Scale are very difficult to identify at the juvenile phase. Once the scale matures it is easier to identify the adult females however it was important to ensure the scale had been correctly identified. Dr Paul Cooper collected samples of juvenile scale in February 2017 for taxonomic identification. Most of the scale present in the vineyard were confirmed to be Grapevine scale with a smaller population of Frosted scale (Photo 13). PHOTO 13: FROSTED SCALE (LEFT PHOTO), GRAPEVINE SCALE (RIGHT PHOTO) 19
10. Summary Vineyards across South Australia were surveyed (informally) for the presence of scale and sooty mould. The regions included in the assessment were Waikerie, Loxton, Auburn, Barossa Valley, Eden Valley, Adelaide Hills, Langhorne Creek, McLaren Vale, Currency Creek and Coonawarra. All of these regions had incidence of sooty mould that were at or above the level of rejection (2% severity). It was observed that scale occurred on some varieties at a higher incidence than other varieties. Riesling, Chardonnay, Grenache and Shiraz showed higher populations of scale than Merlot and Sauvignon Blanc, while the populations of scale on Cabernet Sauvignon were low. Even when a Cabernet Sauvignon block was right next to a Chardonnay block with a very high level of scale, the Cabernet Sauvignon remained clean. Often scale is reported to occur in hot-spots in the vineyard or close to road ways. This was not the case in the vineyards monitored over the last three years. Many of the sites revealed that the majority of the block was infested with scale, to the point that it was not possible to section the vineyard for harvest (ie leave the sooty mould affected fruit unharvested). Scale insects have become a significant pest of vineyards across Southern Australia. It will be important to continue the work with Samurai and the other control agents (Chlorpyrifos and Movento) to ensure growers are able to continue to produce high quality fruit from healthy vineyards. Another impact of scale is their ability to spread Virus. The wine industry needs to be aware that the spread of virus through vineyards by scale and other vectors will be costly for the industry in the future. Sooty mould will continue to cause problems for winemakers while scale is present in the vineyard. The impact of the sooty mould may not be as great in hotter drier years, but while scale insects are present in the vineyard there is the potential for a sooty mould outbreak. Finally, environmental conditions play a major role in the survival of scale and the growth of sooty mould. If seasons continue to become wetter and more humid (see Appendix 1 Weather data) there is a greater likelihood of scale populations increasing. The more scale, the greater level of honey dew and the resultant sooty mould. 20
11. Dissemination of information Grower talks were held in all districts that had scale issues in their vineyards. A list of sessions presented is given below: NSW region: Riverland: Hunter Valley Mudgee Canberra Region Orange Tumbarumba CCW growers PRW growers Mildura and Riverland Clare Valley grower breakfast Adelaide Hills Grower day Langhorne Creek Grower Day McLaren Vale Grower Day Webinar presented to Corporate vineyards annually Webinar via AWRI Poster at the AWITC Adelaide 2016 Individual grower meetings Corporate vineyard working group meetings held at AWRI. 12. Ongoing research Management of Clothianidin residue through the winemaking process. Wine making trials to monitor the impact of sooty mould on wine quality. Review of all pesticides (fungicides, insecticides, herbicides) used in the vineyards to look at the impact they are having on beneficial insect populations. Investigate the use of beneficial insects to control scale. Continue to survey for the identification of scale species in other areas. 21
13. References 1. Buchanan G, 2008. Biological control of grapevine scales. Grape and Wine Research & Development Corporation; DNR 03/01. 2. Camacho ER, Chong JH, 2015. Journal of Integrated Pest Management. 6(1)1-22. 3. Chomnunti P, Hongsanan S, Aguirre-Hudson B, Tian Q, Peršoh D, Dhami MK, Alias AS, Xu J, Liu X, Stadler M, Hyde KD.2014. The Sooty Mould. Fungal Diversity. 66(1) 1-36. 4. Cotsaris D, Burne P, Pietsch A 2009. Fact Sheet No3: Vineyard Scale. CCW Co-operation Limited. 5. Hoare T. 2016. Grapevine scale sucking the profits from vineyards. Wine and Viticulture Journal, 31(2):44-45 6. Hoffmann A, Thomson L, 2011. Development of tools to increase knowledge and capacity of growers to implement sustainable pest management solutions. Grape and Wine Research & Development Corporation; UM 1001. 7. Malumphy C, Eyre D, Cannon R. 2011. Morphology and anatomy of honeydew eliminating organs. In: Ben-Dov Y and Hodgson CJ (eds), Soft scale insects: their biology, natural enemies and control, vol 7A. Elsevier Science B.V., The Netherlands. 8. Rakimov A, Ben-Dov Y, White V, Hoffmann AA. 2013. Soft scale insects (Hemiptera: Coccoidea: Coccidae) on grapevines in Australia. Australian Journal of Entomology. 52: 371-378 9. Rakimov A, Hoffmann AA, Malipatil MB. 2015. Natural enemies of soft scale insects (Hemiptera: Coccoidea: Coccidae) in Australian vineyards. Australian Journal of Grape and Wine Research. 21 (2) 302-301. 10. Simbiken NA, Cooper PD, Powell KS, 2015. Development and feeding effect of Frosted scale Parthenolecanium pruinosum Cocquillet. (Hemiptera: Coccidae) on selected Vitis vinifera L cultivars. Australian Journal of Grape and Wine Research. 21 (3): 451-457 11. Yardeni, A. 1987. Evaluation of wind dispersed soft scale crawlers (homoptera: Coccidae), in the infestation of a citrus grove in Israel. Israel Journal of Entomology. 21:25-31. 14. Acknowledgements This project was generously co-funded by Wine Australia via the Regional Program for SA Central (Adelaide Hills, Currency Creek, Kangaroo Is, Langhorne Creek, McLaren Vale, Southern Fleurieu wine regions). The contribution and cooperation of local landholders is gratefully acknowledged. The generous products, time and expertise support provided by Sumitomo is acknowledged. Support of from the offices of Langhorne Creek Grape and Wine Inc. is gratefully acknowledged. All images (photos) are attributed to Jenny Venus from Landmark Strathalbyn. 22
Appendix 1: Weather data 2014-2017 Weather Data for the three seasons Langhorne Creek Summary of weather data for Langhorne Creek. Year Days below 0 0 C Number of days with Min Temp above 15 0 C through the growing season Days above 35 0 C Rainfall Average RH 2014-15 11 (min -1.8 0 C) 28 16 (max 43.2 0 C) 348.8 73.7% 2015-16 9 (min -1.7 0 C) 40 21 (max 42 0 C) 266 mm 74.6% 2016-17 12 (min -1.5 0 C) 35 18 (max 41.9 0 C) 464.6 77.4% 23
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Appendix 2: Raw data for Trial 1 Scale counts Trial 1 Leaf sample 4/11/2014 3/02/2015 4/11/2014 3/02/2015 4/11/2014 3/02/2015 4/11/2014 3/02/2015 4/11/2014 3/02/2015 Prior to Tmt Orange - Transform Treated Orange - Transform Prior to Tmt Blue - Movento Treated Blue - Movento Prior to Tmt Green - Appluad Treated Green Appluad Prior to Tmt Treated Prior to Tmt Treated Pink - Biopest Pink - Biopest White - Control White - Control Rep 1 1 20 76 32 56 52 18 36 11 26 17 Rep 1 2 115 97 51 82 46 92 52 14 98 92 Rep 1 3 62 83 25 35 115 32 32 132 68 110 Rep 1 4 98 56 0 29 24 12 41 10 114 90 Rep 1 5 25 50 64 44 88 12 91 113 32 23 Rep 1 6 150 79 22 38 19 44 118 48 54 94 Rep 1 7 150 115 138 40 33 52 64 52 62 105 Rep 1 8 45 21 94 0 45 48 52 23 12 22 Rep 1 9 87 45 51 90 62 68 93 36 108 88 Rep 1 10 22 15 150 21 18 57 18 110 150 97 774 637 627 435 502 435 597 549 724 738 77.4 63.7 62.7 43.5 50.2 43.5 59.7 54.9 72.4 73.8 0.82 0.69 0.87 0.92 1.02 18% 31% 13% 8% -2% Rep2 1 150 5 85 94 0 25 92 15 146 110 Rep2 2 29 64 94 10 90 45 118 26 87 10 25
Rep2 3 65 5 110 10 54 98 35 90 11 60 Rep2 4 32 30 22 30 122 60 45 110 110 115 Rep2 5 45 17 35 84 62 50 0 26 35 60 Rep2 6 101 11 64 0 118 11 80 98 64 150 Rep2 7 22 37 55 65 105 52 18 22 85 30 Rep2 8 0 88 122 95 45 23 66 130 62 5 Rep2 9 54 35 12 10 67 132 126 20 44 80 Rep2 10 21 22 109 25 21 29 68 25 19 25 519 314 708 423 684 525 648 562 663 645 51.9 31.4 70.8 42.3 68.4 52.5 64.8 56.2 66.3 64.5 0.61 0.60 0.77 0.87 0.97 39% 40% 23% 13% 3% Rep 3 1 110 32 0 20 10 30 91 143 62 122 Rep 3 2 45 90 28 20 19 29 54 34 45 27 Rep 3 3 22 40 15 40 53 13 67 136 118 15 Rep 3 4 145 38 150 15 86 5 118 45 32 33 Rep 3 5 12 81 51 70 44 62 139 60 136 12 Rep 3 6 78 0 25 18 28 15 5 0 42 52 Rep 3 7 52 25 41 40 36 95 18 20 16 70 Rep 3 8 62 40 92 86 46 52 69 92 46 76 Rep 3 9 31 48 85 115 89 115 23 68 28 80 Rep 3 10 112 20 38 23 115 55 142 54 82 138 Total 669 414 525 447 526 471 726 652 607 625 Average 66.9 41.4 52.5 44.7 52.6 47.1 72.6 65.2 60.7 62.5 26
Difference 0.62 0.85 0.90 0.90 1.03 38% 15% 10% 10% -3% Rep 4 1 32 15 112 40 54 10 64 15 54 35 Rep 4 2 125 40 92 25 62 26 113 20 16 110 Rep 4 3 40 29 54 30 120 12 0 40 119 40 Rep 4 4 32 95 67 20 20 50 29 110 52 110 Rep 4 5 64 36 62 67 49 92 54 35 10 20 Rep 4 6 71 78 55 18 12 56 22 17 18 110 Rep 4 7 12 52 18 70 52 118 135 89 129 35 Rep 4 8 0 17 54 31 31 9 8 18 45 29 Rep 4 9 89 9 67 43 115 126 77 132 108 90 Rep 4 10 115 98 9 91 88 23 120 87 65 49 Total 580 469 590 435 603 522 622 563 616 628 Average 58 46.9 59 43.5 60.3 52.2 62.2 56.3 61.6 62.8 Difference 0.81 0.74 0.87 0.91 1.02 19% 26% 13% 9% -2% Overall total 2542 1834 2450 1740 2315 1953 2593 2326 2610 2636 Overall Average 63.55 45.85 61.25 43.5 57.875 48.825 64.825 58.15 65.25 65.9 0.72 0.71 0.84 0.90 1.01 28% 29% 16% 10% -1% 27
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