Sweet Corn
European corn borer (ECB) moths catches have declined to very low levels over the past week and no map will appear in this edition. The first flight is complete. Feeding percentages have stabilized, and 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 6/19/19 are as follows:
| Crosswicks 1 | Milltown 1 |
| Milford 1 | South Branch 1 |
Scattered corn earworm (CEW) moths continue to be captured in southern NJ blacklight traps through early this week (see blacklight map at left) although these catches have declined since last week. Early plantings, now silking, are at risk of infestation from this pest.
In the CEW pheromone trap network, catches have also declined
but remain highly variable, with higher numbers in the south, and very low activity in northern NJ (see pheromone map below at right). The green area 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 6/19/19 are as follows:
| Woodstown 15 | Pedricktown 5 | Beckett 3 | East Vineland 3 |
| Cedarville 9 | Crosswicks 4 | Berlin 3 | Elm 2 |
| Monroeville 7 | Eldora 4 | Dayton 3 | Jobstown 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.
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.
Bacterial leaf spot infections (see photo at left) have begun to appear 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
With declining ECB moth activity, growers should be looking for ECB egg masses (see photo at left) on the underside of pepper leaves. The larvae that hatch from these eggs will bore into the central stem of pepper plants in the absence of suitable fruit. This damage causes the tops of the plant to die, and eliminating the crown set of fruit in the process. Check 2 leaves per plant on 5 consecutive plants in 10 random locations. Consider treating if 2 or more leaves are found to have ECB larvae on the lower surface.
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. For regional information on this important disease, see the Cucurbit Downy Mildew Forecast webpage: http://cdm.ipmpipe.org/. This weeks’ forecast has southern NJ at moderate risk of infection from sources in the southeastern U.S.
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.
Basil Downy Mildew
Basil DM is now present in southern NJ (see Dr. Andy Wyenandt’s report in the P&PA on 6/13/19. All basil growers should be treating preventively for this disease. In addition, growers should consider utilizing the resistant varieties “Obsession” and “Devotion”, developed at Rutgers University.
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.
