Insecticide For Grapes

While a powerful burst of water may keep away certain plant pests, grape pests are usually hardier and require the use of pesticides to keep their numbers in check. One of four types of pesticides typically controls most grape pests, although a variety of chemicals may be needed for insects that have multiple generations. Always follow the manufacturer’s application rates, and always wear long sleeves, eye protection and an air filtration mask when applying pesticides.

Horticultural Oils and Neem Oil

1. Horticultural oils and neem oil serve as two of the safest — as far as honeybees and natural predators of problem pests are concerned — and more environmentally friendly ways of controlling certain pests. The oils typically do not control pests as well as more toxic chemicals, but they will keep numbers in check unless an infestation has overwhelmed your vineyard. Spider mites, thrips, European fruit lecanium scale and black widow spiders all fall victim to horticultural oils or neem oils. In general, oils work best early in the season, prior to eggs hatching and infestation problems occurring. Apply the oils liberally onto the vine, as contact with the pests is essential.

Spinosad

1. Spinosad is a highly toxic chemical that reacts both on contact and when ingested by the targeted pest. Spinosad is most effective on grape pests that have just entered the larval stage, so the effectiveness of the chemical is directly tied to application timing. Spinosad controls the larvae of cutworms, western grapeleaf skeletonizers, light brown apple moths, thrips, grape leaffolder, orange tortrix and omnivorous leafroller. Spinosad can kill honeybees, so the University of California suggests applying the chemical during the night or morning hours. In the case of a severe infestation, you may reapply spinosad five days after the first application, following the manufacturer’s label rates.

Carbaryl

1. Effective at killing many of the same insects as spinosad, and a few more that spinosad doesn’t take care of, carbaryl is a harsher chemical that’s extremely deadly to honeybees. Because carbaryl can increase mite numbers, never use it where mites are already an issue. It’s effective against branch and twig borers, cutworms, grape leaffolder, hoplia beetles, omnivorous leafroller and orange tortrix. The University of California Integrated Pest Management suggests using carbaryl only when grape vines are in their growing season for orange tortrix and during the second generation for omnivorous leafrollers.

Imidacloprid

1. Imidacloprid works by adversely affecting an insect’s central nervous system. It does not result in immediate death, but eventually will cause the insect to become paralyzed and then die. It extremely toxic to bees and can be harmful to birds and other animals, but it is one of the most effective pesticides to use on many pests. It affects ants, European fruit lecanium scales, ants, grape phylloxera, mealybugs, sharpshooters, leafhoppers, thrips, vine mealybugs and western grapeleaf skeletonizers. You may apply imidacloprid as a foliar spray or soil soak for most insects, although the pesticide comes in a liquid ant bait form for ants.

Stubborn Pests

1. Pests that have multiple generations often require multiple treatments per year and sometimes alternated pesticide types. These insects include European fruit lecanium scales, mealybugs, omnivorous leafroller, orange tortrix and vine mealybugs. Narrow-range oil kills off both generations of European fruit lecanium scales, but imidacloprid only works well against mealybugs in spring, while an application of buprofezin should be made in summer. Spinosad kills the first, second and third generation of omnivorous leafrollers, and both generations of orange tortrix. Vine mealybugs are the most troublesome, and have up to seven generations a year. Applying narrow-range oil at the very start of spring and then using imidacloprid in summer, or splitting up two applications of imidacloprid between when the vine’s bloom period and in the middle of summer, works best. Grape bud beetles and vinegar flies do not respond to carbaryl, imidacloprid, horticultural oils or spinosad. Pyrethrin works well against vinegar flies, while phosmet or dimethoate takes care of grape bud beetles. No pesticide specifically targets leadcable borer, blackvine weevils or click beetles, but they usually appear with other insects and are affected by pesticides that affect those insects.