Sweet Corn
The black light trap network in New Jersey is now operational. To date, one corn earworm (CEW) at Green Creek (Cape May County), and several European corn borer (ECB) moths have been captured. As numbers increase, look for population maps of ECB, CEW, brown marmorated stink bug (BMSB) and CEW catches from pheromone traps in this weekly publication. The resulting full-state maps will include interpretive information.
The highest nightly trap catches of ECB for the week ending 5/19/21 are as follows:
| Centerton 1 | Jones Island 1 |
| Clinton 1 | Woodstown 1 |
Cole Crops
Low numbers of imported cabbage
worm (ICW at left) continue in cole crop plantings in central and northern NJ, and adults are evident everywhere. With warmer temperatures on the way, these infestations should increase rapidly. Check 5 consecutive plants each in 10 random locations throughout the planting, paying particular attention to the innermost leaves where ICW often feed (see photo at lower right). Consider treating if caterpillars are found on 10% or more plants that are in the 0-9 true leaf stage. From 9-leaf to the early head stage (in broccoli, cauliflower, and cabbage) infestations up to 20% may be tolerated. Once heads begin to form, a 5% threshold should be observed to protect the marketable portion of 
the plant. For leafy greens such as collards and kale, 10% plants infested is the threshold throughout.
Although IPM personnel have not detected any diamondback moth larvae (DBM) in scouted plantings, they are certain to appear very soon. Remember that some populations of DBM are resistant to carbamate and synthetic pyrethroid insecticides. The lack of DBM control with these insecticides has been noted in NJ previously. It is important to distinguish between common cole crop pests for this reason. DBM larvae grow to a length of approximately 0.5”, and taper toward both ends (see photo at lower right). 
These caterpillars thrash violently when disturbed. ICW grow to a length of approximately 1.25” and are covered with short hairs. Some chemistries that specifically target caterpillar pests are effective against DBM as well as all other caterpillar pests of cole crops. These materials include (active ingredient – trade name (IRAC* code)):
Spinosad/Spinetoram – Entrust/ Radiant (5)
Chlorantraniliprole – Coragen (28)
Cyantraniliprole – Exirel (28)
The IRAC group 5 insecticide, Entrust, is OMRI approved for organic production. Insecticides based on the soil-inhabiting bacterium Bacilllus thuringiensis (B.t.) may also be effective on caterpillar pests of cole crops. Examples include Xentari and Javelin.
Flea beetles remain very active in a number of plantings, and warmer days will accelerate injury. Signs of “shot-hole” in leaves of host crops are an indication that flea beetles are present, even if the pests are not visible due to cold/wet weather. These pests have a preference for the “hotter” flavored crops like arugula, mustard greens, and turnip greens. They also attack Tuscan or lacinato kale frequently. Plants may be protected with at-planting, soil-applied neo-nicotinoid insecticides (see the 2020/21 Commercial Vegetable Production Recommendations for products). An OMRI approved foliar material for flea beetle management is Pyganic. This product will provide knock-down of flea beetles, but may need to be applied frequently on preferred host crops.
Allium leaf miner
No captures of allium leaf miner (ALM) adults on sticky cards in Hunterdon or Mercer counties have occurred over the past two weeks. It is likely that the first flight is now over.
Tomatoes
Field scouting of outdoor and high tunnel tomatoes has begun. As yet, no insect/mite pests have been detected, but aphids (see photo at right) and two-spotted 
spider mites are the first pest problems to occur on high tunnel tomatoes. Growers should check these tomatoes at least weekly, and note the presence of mites or aphids. Mites in particular should be treated early, so that they do not build to a population that becomes difficult to manage. Aphids are often preyed upon by syrphid fly maggots, ladybird beetles, and serve as hosts for parasitic wasps. However, if cool weather dictates that the sides of the tunnels remain down, parasitism and predation may not occur. Generally, aphids become a nuisance on tomatoes when their droppings accumulate on the surface of developing fruit. If no fruit are present, chemical control is less urgent. Consider treating if aphids are found on multiple sites in a 5-site sample, and fruit are beginning to develop.
