Sweet Corn
The first European corn borer (ECB) flight is over, and no map will appear in this edition. Feeding percentages are now declining as affected plantings get treated and pass to the silk stage. No new feeding should occur until the second flight arrives.
Growers should continue to scout whorl and pre-tassel stage plantings weekly and consider treating when infested plants exceed 12% in a 50 plant sample. As plantings proceed to the pre-tassel stage, ECB larvae may be found in emerging tassels. It is a good idea to treat individual plantings as they move into the full tassel/first silk stage one time. This eliminates any ECB larvae that have emerged with the tassels as they begin to move down the stalk to re-enter near developing ears.
Useful insecticides for this particular application include synthetic pyrethroids (IRAC Grp 3), spinosyns (including OMRI approved Entrust) IRAC Grp 5), and diamides such as Coragen (IRAC Grp 28) or materials such as Besiege which include the active ingredient in Coragen. Synthetic pyrethroids alone should NOT be used for corn earworm (CEW) protection on silking corn. Control with these materials is very inconsistent.
The highest nightly trap catches of ECB for the week ending 6/26/19 are as follows:
| Cedarville 1 |
| Denville 1 |
| Hillsborough 1 |
Corn earworm (CEW) moth catches in both trap types have decline dramatically over the past week (see blacklight map at left, and pheromone trap map below at right). We are entering the time of the season when CEW activity is at its’ lowest. Despite this, low numbers continue in southern NJ blacklights and in the much more sensitive pheromone traps. The overwhelming majority of activity is below Mercer County, with only scattered individuals in northern areas. Green areas on the pheromone trap map indicates a 4-5 day silk spray schedule. Blue areas represent a 5-6 day schedule, and white areas are 6-7 day. There
are far fewer CEW pheromone traps than blacklights, and the resulting map has much broader color bands as a result. It should also be noted that the pheromone traps are much more sensitive than blacklights. Therefore, the number of moths caught in pheromone traps required to generate a specific spray interval is much higher than the number caught in blacklight traps. It must be stressed that there is high variability in these catches, and growers should consult with their IPM practitioner on recommended spray schedules.
The highest nightly trap catches of CEW pheromone trap catches for the week ending 6/26/19 are as follows:
| Woodstown 14 | Pedricktown 5 | Jobstown 3 | Eldora 2 |
| Cedarville 8 | Crosswicks 3 | Beckett 2 | Farmingdale 2 |
| Monroeville 8 | Elm 3 | Berlin 2 | Springdale 2 |
Silking Spray Schedules*:
South – 4-5 days
Central – 4-5 days
North – 6-7 days
*These recommendations are based on regional catches. Adhere to tighter spray schedules if indicated by local trap catches. To repeat: Synthetic pyrethroids alone should NOT be used for corn earworm (CEW) protection on silking corn. Control with these materials is very inconsistent.
Tomatoes
Two-spotted spider mites (TSSM) have begun to appear in some plantings. This pest, if not controlled, can result in significant drying and loss of foliage. Early signs of building infestations are whitish pin spots called a “mite stipple” (see photo at left). Look for these spots on leaves that cup downward and are in the lower canopy. As mites progress, these spots will coalesce into broad yellow areas on the leaflets and will appear higher on the plant. Weekly scouting is necessary for TSSM, and 
control should be initiated early. Large infestations are difficult to manage. See the Tomato Section of the 2019 Commercial Vegetable Production Guide for recommended miticides. IPM technicians have begun to find tomato hornworms (THW) in some high tunnel tomato plantings this week. These caterpillars (see photo at right), can cause unacceptable levels of damage to foliage and green fruit in high tunnels, while they are rarely a significant problem in the field. If evidence (stripped leaves, droppings or actual hornworms) of these pests are found at multiple sites in the high tunnel, consider control. This can be by hand picking or with insecticides like Coragen (IRAC 28) or Entrust (IRAC 5 – OMRI approved).
Bacterial leaf spot infections (see photo at left) are increasing in some fields following heavy rains. Look for very dark lesions on leaf margins, and on the interior of immature leaves. Lesions will have chlorotic borders and may cause immature leaves not to expand properly. Growers should treat preventively for this disease prior to symptoms. See the tomato section of the 2019 Commercial Vegetable Recommendations Guide for materials and spray schedules.
Peppers
As yet, no pepper weevils have been captured on traps placed near southern NJ pepper fields.
Pumpkins and Winter Squash
With pumpkin and related crop fields now being planted, it is important to remember that the initial threat will be from striped cucumber beetles. Most seeds now come with a pre-applied insecticide to limit injury from this pest. However, growers should be alert to the possibility that untreated seeds may be fed upon heavily by cucumber beetles, resulting in bacterial wilt in a few weeks, or outright death of seedlings from excessive feeding. Scout 5 plants each in 10 random locations. If beetles are found to be feeding at more than two sites, consider an insecticide application to limit damage. It is unlikely that this situation will occur if seeds were pre-treated.
A cucurbit downy mildew sentinel plot is now established at Snyder Farm in Hunterdon County. This plot, consisting of pumpkin, watermelon, cantaloupe, butternut, acorn, cucumber and kabocha squash will be used to indicate the presence of cucurbit downy mildew in the region, and what crops are affected. The closest documented occurrence of CDM comes from Caroline County, MD and is affecting cucumbers. For regional information on this important disease, see the Cucurbit Downy Mildew Forecast webpage: http://cdm.ipmpipe.org/. This weeks’ forecast has NJ at minimal risk risk of infection from sources to our south.
Potato Leafhopper
Potato leafhopper (PLH) adults (see photo at left) have appeared in snap beans and other crops over the past two weeks. This pest is a particular problem because it often goes unnoticed until foliar distortion and burn occurs. Once this damage appears in beans and some potato varieties, yields have already been compromised. It is critical that beans be monitored regularly for the presence of PLH. If a sweep net is available, consider treating if more than 100 nymphs and adults are present in 20 sweeps of pre-bloom stage plants. This threshold increases to 250 during bloom and to 500 per 20 sweeps during pod development. If no sweep net is available, check plants in 10 random field locations and consider treating if adults and nymphs are found throughout. Adults are pale green, and will fly out from foliage when disturbed and immediately fly back into the plant canopy. Nymphs are wingless and bright green and may be found on the underside of leaves.
Cole Crops
Reminder: Destroy crop residue!!
As cabbage, kale, etc. plantings exceed their prime harvest, do not wait long to incorporate all residue into the soil. This prevents the crop residue from becoming a nursery area for pests like crucifer flea beetle and diamondback moth larvae.
2019 Vegetable IPM Program Personnel
Kris Holmstrom and Joe Ingerson-Mahar would like to acknowledge the IPM Field Technicians for this season:
Owen Donnelly
Dottie Hansbury
Kaitlin Quinn
Brooke Prusa
Without the assistance of these individuals, much of the information presented in this publication would be unobtainable. We are grateful for all their help and hard work.
