HOP INSECT PESTS

Insects can generate large numbers very quickly. Your best defense is to check your plants daily or even twice daily, morning and evening, especially in the early stages of growth. Problems can be corrected and damage reduced if caught early.

Hop Aphid (Phorodon humuli)

Hop AphidA frequent pest on hops. It passes the winter as an egg on woody hosts of the genus prunus(cherry, peach, plum). Winged aphids move to the top of the plant late in the spring. Aphid populations may build very rapidly and if left uncontrolled may result in defoliation.

Twospotted Spider Mite (Tetranychus urticae)

mobile adultMobile Adult(#1)
A serious pest of hops grown in the warm interior valleys of the northwestern United States.
mite webs Mite Webs(#2)
Part of the reason mites are difficult to control is due to the webbing. Mite webs protect eggs and mobile mites from contact by sprays. Webbing is usually confined to the main interveinal areas of the underside of the leaf.
mite damage Mite damage (#3)
Mites damage hop leaves by inserting needle-like mouthparts into plant cells and pumping out the contents. Injury appears as light colored spotting. Such feeding injury is an early clue in detecting an infestation of mites.
Control Options vary with the intensity of the infestation. Removal by hand, pulling the leaves off and destroying them, or using a hose to knock them off with water. Or you can use deterents like pepper sprays or garlic sprays. Planting borders of flowers such as African marigold, nasturiums and garlic plants will help deter the numbers in the early stages of growth. Organic insecticides such as Pyrethrum, insecticidal soap, nicotine and diatomatious earth work well if effectively applied. Some success can be derived via the introduction of ladybugs and lacewing predator insects as long as the predators decide to stay on the hops. But if the infestation has gone unchecked, when discovered, using commercial insecticides such as diazinon or malathion sprays maybe your only option to try and save the crop.

An ounce of Prevention is worth a pound of hops.


Text and Photos courtesy of:
J.R. Simplot Company
Pocatello, Idaho 83201


Counter installed 07/20/97