International Soft Fruit Conference s Hertogenbosch

Transcription

1 International Soft Fruit Conference s Hertogenbosch Tracking the blackberry mite (Acalitus essigi) Phenological observations and control Matthias Bernhart Landratsamt Ortenaukreis Amt für Landwirtschaft Prinz-Eugen-Str Offenburg Tel.: Fax: matthias.bernhart@ortenaukreis.de

2 Ortenau district fruit production Southwest of Germany Rhine valley and black forest ( m) One of the warmest regions in Germany (9,8 C average temperature, mm precipitation) 4500 ha fruit production, most in open field: pomefruit, stonefruit and soft fruits

3 Introduction: Blackberry gallmites in Ortenau district Every year blackberry growers find fruits with symptoms, which could be origin from mites. On such fruits we could not find mites (Microscopic observation). 2014: heavy damages on Loch Ness,, cultivated in a glasshouse => frequent applications with Vertimec short effect 2015: only some sites with damage; in autumn 2015 control of canes origin from different blackberry sites:discovery of lots of mites behind the basic flakes of new buds on different varieties: Loch Ness & Loch Tay in the field and glasshouse Chester from open field

4 2016: More exact examinations Glasshouse plantation Loch Ness Microscopical observation of buds and lateral shoots (interval of 1 week/ 3 weeks): presence of mites Field test: effect of sulphur applications on the blackberry mites

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6 Microscopical observation of buds LANDRATSAMT ORTENAUKREIS

7 Autumn 2015: control of buds ( ) House 2 left and right side Ø mites alive/ bud Ø mites dead/ bud H2li (n=20 buds) 2 4 H2re (n=18 buds) 4 0 Spring 2016: first control of buds ( ) House 2 left and right side Ø mites alive/ bud Ø mites dead/ bud H2li (n=20 buds) 2 4 H2re (n=18 buds) 4 0 Some canes with high numbers of mites/ bud: mites/ bud

8 Observation on base and in the axils of lateral shoots Bilder: Bernhart Bild vom Bild vom

9 date LANDRATSAMT ORTENAUKREIS 2016: observation of lateral shoots average number Mites/ bud Oviposition on a few buds Mites behind basic flakes ~ 10 Mites behind basic flakes ~ 25 Mites behind basic flakes ~ 50 Movement to the axils ~ 70 increasing oviposition Bild vom

10 Observation of lateral shoots: average LANDRATSAMT number ORTENAUKREIS of mites N= 6 / N= 6 / N= 3 / base untreated N= 3 / 1. leaf/ axil untreated leaf / axil untreated leaf/ axil untreated tot 4. leaf/ axil untreated tot Blossoms/ flowers untreated tot oviposition untreated Strong on base On base and in axils strong in 4. axil no

11 Is there an effect of sulphur applications on gallmites? Test in the glasshouse 1. application on with 7 kg/ ha Kumulus WG 2. application on with 4 kg/ ha Kumulus WG Control of the evolution of the mite population on treated plants compared to untreated

12 Observation of lateral shoots: average LANDRATSAMT number ORTENAUKREIS of mites Position of the bud Variante N= 6 / N= 6 / N= 3 / N= 3 / 2 Base untreated sulphur leaf untreated sulphur leaf untreated sulphur 0 2, tot 3. leaf untreated tot sulphur 0, tot 4. leaf untreated tot sulphur 0, tot flowers untreated tot sulphur oviposition untreated Strong on base On base + axils strong in 4. axil none sulphur a few on base a few on base none None Grünberg - Beerenobstberater 2016

13 Bilder: Beuschlein vom

14 Bild: Bernhart Bild: Pfundstein, vom

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16 Symptoms on Chester in begin of September Bilder: Bernhart (1), Beuschlein (2)

17 Bilder: Beuschlein

18 Conclusion Blackberrymites occur often in the blackberry production in the Ortenau region in open field and glasshouse production Blackberry mites live covert in axils or behind flakes of buds Symptoms described in literature as origin from Acalitus essigi can be confirmed Glasshouse production: 2 applications of sulphur within two weeks can stop the evolution of blackberrymites up to six weeks There were no phytotoxical reaction after the application of sulphur in the glasshouse production in 2016 (cloudy weather) The effect of sulphur applications in the open field must not be the same as in the glasshouse sulphur may be washed away by rain 2017: large field trial to check the efficacy of different acaricides no symptoms, too little numbers of mites during the growth period

19 Thank you for your attention!