Vegetable Crop Insects – July 15, 2016

Joanne Whalen, Extension IPM Specialist;

Lima Beans
Continue to sample for mites since early detection is necessary to achieve effective control. Labeled products include bifenazate (Acramite), bifenthrin (numerous generics labeled), dimethoate, Hero (combination of bifenthrin and zeta-cypermethrin), and recently labeled Agri-Mek SC (reminder — this is the only labeled formulation). Be sure to read all labels carefully for all restrictions including but not limited minimum gallonage needed by air, days between applications, pre-harvest intervals, and adjuvants requirements that must be followed to avoid illegal residues. We are starting to see an increase in stinkbug and plant bug populations. As soon as pin pods are present, be sure to watch carefully for plant bug and stinkbug adults and nymphs. As a general guideline, treatment should be considered for lygus if you find 15 adults and/or nymphs per 50 sweeps. For stink bugs, the threshold should be reduced by one half.

Continue to scout all melons for aphids, cucumber beetles, and spider mites. Although aphid populations still remain low in most fields, we are starting to see localized infestations. At this time of year, early detection is critical since populations can quickly explode. It is also the time of year to start watching for caterpillars that feed on rinds which can include beet armyworm, yellow striped armyworm, and cabbage looper larvae. If beet armyworm is in the mix, it is important to select a material that is effective on this insect (refer to the Commercial Vegetable Recommendations) – the pyrethroids do not provide effective control. Be sure to read all labels carefully for pollinator protection statements, rates and restrictions. Some materials are restricted to only one application as well as ground application only.

Depending on local corn borer trap catches, sprays should be applied on a 7 to 10-day schedule once pepper fruit is ¼ – ½ inch in diameter. Be sure to check local moth catches in your area by calling the Crop Pest Hotline (302-831-8851) or visit our website at At this time, you will also need to consider a treatment for pepper maggot.

Snap Beans
Depending on local trap catches, sprays may be needed at the bud and pin stages on processing beans for corn borer control. As earworm trap catches increase, an earworm spray may also be needed at the pin stage. You will need to check our website for the most recent trap catches to help decide on the spray interval between the pin stage and harvest for processing snap beans. Once pin pods are present on fresh market snap beans, a 7 to 10-day schedule should be maintained for corn borer and corn earworm control.

Sweet Corn
Continue to sample all fields through pre-tassel stage for whorl feeders (corn borer, corn earworm and fall armyworm). A treatment should be applied if 12-15% of the plants are infested with larvae (regardless of the species). The predominant whorl feeder being found at this time is the fall armyworm. Since fall armyworm (FAW) feed deep in the whorls, sprays should be directed into the whorls and multiple applications are often needed to achieve control. FAW can also be a problem in silk stage sweet corn, especially in outbreak years. The first silk sprays will be needed for corn earworm as soon as ear shanks are visible. Be sure to check both blacklight and pheromone trap catches since the spray schedules can quickly change. Trap catches are generally updated on Tuesday and Friday mornings on our website ( and the Crop Pest Hotline (302-831-8851). Information on scouting sweet corn and how to use the trap catch information can be found at