Vineyard Insect Management what does a new vineyard owner/manager need to know? Keith Mason and Rufus Isaacs Department of Entomology, Michigan State University masonk@msu.edu isaacsr@msu.edu
Insect management in vineyards Most insect and mite species are not pests Some are pests, so you should learn to recognize them They can ruin your crop, reduce yield, encourage disease Weekly vineyard scouting can help avoid surprises The goal is to maintain a canopy that can ripen your new vine growth, and ripen your crop.
Scouting is the foundation of vineyard IPM Scouting helps vineyard managers know when pests are present, and at what levels. Early detection avoids outbreaks. Scouting information helps ensure chemical inputs are applied only when needed. This is an essential component of reliable and economical production of high-quality grapes.
Scouting in your vineyards Options for growers - independent IPM scout - distributor representative - do it yourself * not hard to learn * learn as you go * gain knowledge of your vineyard
Grape scouting form This form available online at www.isaacslab.ent.msu.edu/grapescout/scout.pdf
Key vineyard insect pests to scout for Cutworm Flea Beetle Rosechafer Phylloxera Grape Berry Moth Japanese beetle Leafhoppers Mites Yellowjackets Ladybeetles
Key times for grape insect scouting and management Bud swell Cutworms/flea beetle Pre-bloom Rosechafer, cane girdler Postbloom GBM, leafhoppers, rosechafer July GBM, leafhoppers, Japanese beetle August GBM, Japanese beetle, mites pre-harvest yellow jackets, ants, ladybeetles, spotted wing Drosophila
Cutworm" can be any of a large number of moths. Larvae are night feeders of many plants, including grape vines, damaging mainly buds and young leaves.
If detected, aim is to prevent further damage in subsequent nights Action threshold of 2% bud damage (juice grapes) when buds are susceptible. Climbing cutworm damage
Grape Flea Beetle Appearing at bud swell, these beetles feed on buds and can cause yield loss and stunt vine growth. Summer adults and immatures feed on tender leaves.
Eggs are laid mainly under bark, but some are laid on bud scales and top of leaves. Larvae eat leaves but not the veins; fall to the ground to pupate less than 1/2 inch deep. Use same threshold as for cutworms
Rose Chafers Light tan beetle with long legs Adults emerge from grassy areas during bloom Feed on leaves and clusters
Root form is of concern on vinifera vines. Managed with resistant rootstocks Grape phylloxera Leaf galling can look terrible on some hybrids. But, easy to control with some new insecticide options
Grape berry moth A major pest in southern Michigan. Only on vines with berries.
Berry moth life cycle EG G LARVA PUPA ADULT Generation 1: bloom Generation 2: mid-season Generation 3: veraison-harvest A degree day model is available to help time controls for this pest
Larvae inside the berry grow and cause visible damage: webbing, discoloration. A single larva can damage many berries
Entrance points are easy to spot. Mature larva
GBM infestation is typically greater on the vineyard border % infested clusters 80 70 60 50 40 30 20 SW Michigan High risk vineyard Gen 1 Gen 2 Gen 3 10 0 BORDER INTERIOR
Japanese beetle life cycle (Michigan timing)
Scouting or monitoring for beetles? SCOUTING Beetles and their damage are easy to see Look on upper canopy Assess percent of leaf area lost MONITORING TRAPS Highly efficient at attracting beetles, and may be effective in reducing isolated populations But, these will attract beetles to your vines, so do not place in vineyards.
How much leaf injury can vines tolerate? Virginia study In mature Seyval vines, natural levels of Japanese beetle feeding (6.5% leaf area loss) had no effect on vine growth or fruit quality. Intensive feeding after veraison inside cages (11% leaf area loss) reduced fruit quality Michigan study In young Niagara vines without crop, 30% leaf area loss affected vines only when they were damaged at bloom and at veraison
Leafhoppers Grape Leafhopper Erythroneura comes Potato Leafhopper Empoasca fabae Overwinters near vineyards and moves to grapes in late May-June. Affects labrusca vineyards more Comes with the wind in spring, washed onto crops by rain showers. Probably dies in winter. Affects vinifera and hybrids more
Grape leafhopper (juice grapes/hybrids) Potato leafhopper (wine grapes) Leafhoppers tend to stay on undersides of leaves Damage is visible as discoloration.
Mites Two-spotted spider mite (rare) European red mite (very rare) Symptoms start as light bronzing Need a hand lens to see mites Include in your regular scouting, and look for predatory mites Rarely an issue in IPM-managed vineyards
Predatory mites usually keep plant-feeding mites in check, if they are not disrupted Two spotted spider mite Predatory mite 10:1 ratio of pest to predator mites provides effective biological control
Maintain scouting until harvest Harvest pests are easy to see, but only if you keep scouting Prevents late-season surprises Some sporadic pests appear at harvest Multicolored Asian ladybeetle UMN presence/absence sampling and threshold Sample 26 clusters at random per block At 5 infested clusters per sample, 10% of consumers can detect the taint Yellow jackets Fruit flies Ants Mealybugs
Vineyard Natural Enemies predator Predatory mites prey Pest mites Lady beetles Soft-bodied insects Hoverflies Soft-bodied insects Lacewings Soft-bodied insects Parasitic wasps Leafhoppers, moth larvae Ground predators Varied prey on ground and on the vine
Some MSU pest management resources Order publications at bookstore.msu.edu E-154 Print copy $25 PDF for $20 E-2889 $20 Free fruit updates at msue.anr.msu.edu during the season
Questions?