Insect observations

A few Japanese beetles were sighted today on a peach tree in Columbus. Late June is the usual time that this pest begins to emerge. Beware that large congregations might be seen on their preferred crops over the next few weeks. Japanese beetle is a pest of sweet corn, snap beans, raspberries, grapes, plum, peaches, blueberries, and hops as well as ornamental plants such as roses and linden trees and sassafras, and weeds such as smartweed. This pest can be more readily controlled by insecticides if the spray is made when the congregations are just beginning to form. Insecticides that are very effective for control of Japanese beetle are old ones: carbaryl (Sevin) and pyrethrins plus PBO (EverGreen Pro).

True armyworm is active in corn fields and grassy areas. We previously reported a large surge in the number of armyworm moths caught in our blacklight trap in Columbus between 5/14 and 5/18, with a record of 210 moths in one night on 5/14. We have been seeing increased numbers of moths during the past week, including today when there were 96 armyworm moths in the trap. There have been reports of armyworm larvae being found in field corn fields around Ohio. Daily counts of armyworm and several other common moths in blacklight traps are posted here:

Squash vine borer is now active, and abundant at our research farm in Columbus. Its adult is a day-flying moth that will be laying eggs on zucchini and other summer squash, winter squash (except butternut), pumpkins, and gourds over the next few weeks. It generally is a severe problem in home gardens and in small plantings, but less severe in large fields. Insecticide can be effective if directed to the base of the main stem before eggs have hatched, usually at least 2 or 3 sprays at 10-day intervals. Insecticides used for its control are pyrethroids such as Asana (esfenvalerate), Pounce (permethrin), Warrior (lambda-cyhalothrin), MustangMaxx (zeta-cypermethrin), or Brigade (bifenthrin); it is usually not well controlled by Sevin (carbaryl). We have found that EverGreen Pro (pyrethrins plus PBO) is effective although squash vine borer is not listed as a target pest on its label. This year we have a field trial in progress to evaluate the non-chemical tactic of a border trap crop of unharvested zucchini.

Corn earworm has been active for the past few weeks but at low numbers, which is typical of this pest in Ohio in early summer in most years. We have not seen the surge in moth activity like we did last year in late May and early June. A pheromone trap is highly effective at detecting the presence of the moth. Farms with early planted sweet corn should have their trap out as soon as tassels are emerging. Information on using traps is available here:   Information on buying traps to monitor corn earworm is here: . Trap counts from several Ohio locations are posted here:

Potato leafhopper is active and being reported from beans, potatoes, apples, and hops. The adults and nymphs of this pest are found on leaf undersides where they suck sap. Their feeding results in yellowing then browning along the edge of leaves, a symptom known as ‘hopperburn’. Leafhoppers can be controlled by sprays of a neonicotinoid such as Admire (imidacloprid) or Assail (acetamiprid), or a pyrethroid such as Pounce (permethrin), Warrior (lambda-cyhalothrin), MustangMaxx (zeta-cypermethrin), Brigade (bifenthrin), or by dimethoate.

Brown marmorated stink bug is active now. Our traps are catching only adult stink bugs so far, but a few young nymphs have been seen on host plants. This year we are continuing our investigations of the samurai wasp, which is a tiny parasitoid that specializes in killing the eggs of this stink bug. We have a colony of the samurai wasp at OSU, and we have made releases of it at ten Ohio fruit farms, in comparison with 10 Ohio fruit farms where we did not make a release. We are currently sampling those 20 farms to see if the samurai wasp has become established.

Spotted lanternfly: This invasive exotic pest has NOT yet been found in Ohio, but many people are on the lookout for it, especially in eastern Ohio, because it has been spreading from its initial infestation in eastern Pennsylvania. Its favorite host plant is the tree of heaven but it can cause damage to grapes, hops, blueberries, and other fruit crops, mostly in late summer.

-Celeste Welty, Extension Entomologist

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