Catches of European corn borer (ECB) have declined through much of the state. Remaining areas of highest activity include parts of Monmouth, Mercer and Salem counties (see ECB map). ECB infestations are now rising in sweet corn plantings, but are well below normal levels. Feeding ranges from single digits to 20% in areas where IPM personnel are operating, but many plantings have no detectable feeding at all. Be sure to begin monitoring plantings for ECB feeding while they are still in the whorl stage. Consider treating when the number of infested plants in a 50 plant sample exceeds 12%. Feeding in the whorl stage will appear as numerous small holes (called “shot-hole”) on leaves, with damage present on consecutively younger leaves. As plants progress to pre-tassel and beyond, the actual larvae may be found in or on the emerging tassels (see photo). Any planting remaining at or above threshold as it proceeds to full tassel should be treated, as this is the last stage at which ECB larvae will be exposed and vulnerable to insecticidal sprays. Often, early sweet corn plantings suffer from “split set”, in which germination does not occur in a uniform
fashion. The result is a planting where all plants do not reach full tassel at the same time. This situation may require an extra tassel spray if there are several days difference in the time full tassel is reached on a significant number of the plants. Insecticides that are acceptable in organic production include the spinosyn based material Entrust (IRAC-5) and Dipel (IRAC-11a). The 10G formulation of Dipel is particularly useful when granules can be dropped or broadcast such that they get into the whorls of corn plants. See the 2016 Commercial Vegetable Recommendations Guide for more insecticide choices.
The highest nightly ECB catches for the previous week are as follows:
|Allentown 1||Eldora 1||Lawrenceville 1|
|Cinnaminson 1||Folsom 1||Pedricktown 1|
|Denville 1||Hackettstown 1||Princeton 1|
|Downer 1||Jones Island 1||Sergeantsville 1|
Corn earworm moth (CEW) captures in blacklights have declined this past week. This may be due to cooler evening temperatures as well as the normal decline of this early adult population. Present adult activity from blacklights is confined to the Delaware Bayshore (see CEW map).
The highest nightly CEW catches for the previous week are as follows:
|Cinnaminson 1||Jones Island 1|
|Eldora 1||Pedricktown 1|
In addition, a limited number of CEW pheromone traps have been deployed throughout the southern counties. These traps have captured low numbers of CEW moths (see CEW pheromone map). The broad color patterns of this map are a result of the few numbers of contributing trap sites. As sweet corn plantings begin to silk, it is critical that growers monitor local CEW moth numbers. These early season moths target sweet corn exclusively and result in a level of damage that seems out of proportion to their numbers. For the present time, any sweet corn plantings entering the silk stage should be treated to limit CEW injury as well as to prevent ear damage from ECB larvae that already inhabit the stalks.
The highest nightly CEW pheromone trap catches for the previous week are as follows:
|Pedricktown 5||East Vineland 1|
For silking sweet corn, the following spray schedules are warranted.
Silking Spray Schedules*:
South – 5-6 days
Central – 7 days
North – 7 days
*These recommendations are based on regional catches.
Young pepper plants are at risk of infestation from this first ECB generation. Be sure to scout fields regularly for the presence of ECB egg masses. If two or more egg masses are found in a 50 plant (two leaves/plant) sample, consider treating even if no fruit are present. In the absence of fruit, ECB larvae will bore into the central stem, topping the plant. This will result in the loss of crown fruit on infested plants. Generally, where blacklight trap catches average one or more ECB per night (blue and green areas on the ECB map) and fruit are greater than ½” in diameter, insecticides are warranted. See the 2016 Commercial Vegetable Production Recommendations for materials useful in controlling ECB.
Pepper Weevil Report
No weevils have been trapped at the processing facilities that we are monitoring. So far, no weevils have been caught in monitored fields and there are no reported infested fields.
Brown Marmorated Stinkbug (BMSB)
A few BMSB have been captured in NJ blacklight traps this week. Numbers are still quite low. As this pest increases, maps will appear in this newsletter.
The highest nightly BMSB pheromone trap catches for the previous week are as follows:
|Pedricktown 3||Farmingdale 1||Crosswicks 1|
|Allentown 2||Matawan 1||Georgetown 1|
Pumpkins and Winter Squash
These crops are now emerging in many areas. It is important to monitor frequently for the presence of striped cucumber beetles at this time, particularly if the seed was not purchased pre-treated with an insecticide for cucumber beetle. Check 5 consecutive plants each in 10 random locations. Examine upper and lower surface of seed leaves for the presence of beetles. Consider treating if beetles are found at 5 or more sites. Heavy, but local infestations may be spot treated. Management of these pests will limit the loss of plants to the bacterial wilt disease that the beetles transmit.