Sweet Corn
There have been very modest increases in European corn borer (ECB) moth captures this past week. Most measurable catches occurred in central and northwestern Burlington County (see ECB map at left). These individuals represent a second flight. The next 2 weeks will give us an indication of how significant this flight will be. In recent years, the second and later flights have been very low. New feeding should appear within 2 weeks, but may be obscured by fall armyworm (FAW) feeding by that time.
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 7/17/19 are as follows:
| Califon 1 | Folsom 1 | Milltown 1 |
| Cinnaminson 1 | Green Creek 1 | Sergeantsville 1 |
| Crosswicks 1 | Hillsborough 1 | |
| Dayton 1 | Medford 1 |
Corn earworm (CEW) moth catches in both trap types increased again over the past week (see blacklight map at left, and pheromone trap map below at right). Catches from North Carolina remain variable and not particularly high, while Delaware’s catches are similar to our southern NJ catches. While none of these catches indicate that a large scale migratory influx is underway, the unstable weather forecast for Thursday and Friday of this week may result in further increases. Even with the recent minor uptick in moth catches, numbers are low-to moderate in southern and central NJ, with the majority of activity below Middlesex County. 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 7/17/19 are as follows:
| Green Creek 25 | Woodstown 14 | Beckett 7 | Cedarville 3 |
| Pedricktown 19 | Eldora 10 | Dayton 5 | Farmingdale 3 |
| Monroeville 14 | Springdale 8 | Elm 5 | Jobstown 3 |
Fall Armyworm
Fall armyworm (FAW) continue to feed to a limited extent in some Cape May County sweet corn fields, and a very low level infestation was just discovered this week in the New Egypt area of Ocean County. We are entering the time of the season when FAW usually begins to increase. This pest causes extensive foliar damage on whorl stage corn (see photo
at left), can also infest ears, and is capable of killing small plants. For this reason, regular field scouting of all plantings including seedling stage corn is necessary. FAW larvae are brown in color (see photo at right), with an inverted 
“Y” pattern on their head capsule. They are much larger than ECB when fully developed. FAW is even more consistently resistant to pyrethroid insecticides. For this reason, the same insecticides classes now recommended for CEW control should be utilized for FAW management.
Silking Spray Schedules*:
South – 4 days
Central – 4-5 days
North – 6 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, or for fall armyworm (FAW) management at any stage. Control with these materials is very inconsistent.
Tomatoes
We are entering the period of the growing season when stinkbug activity in tomato fields increases, and higher levels of feeding have been reported by technicians. These insects feed on fruit, causing the characteristic “cloudy spot” injury (see photo at left). Stinkbug nymphs cannot fly, and will feed extensively on fruit in discrete locations. Often picking crews detect feeding first, due to the volume of fruit they handle. If feeding is increasing or immature stinkbugs are detected in fields, or adults are detected at more than one site in a ten site sample, consider insecticide applications to limit injury. Consult the Tomato Section of the 2019 Commercial Vegetable Recommendations for suggested materials.
Peppers
As yet, no pepper weevils have been captured on traps placed near southern NJ pepper fields.
Bacterial leaf spot infections are occurring with more frequency throughout the state. Dark lesions at the leaf margins, with a water-soaked appearance are typical of this disease (see photo at right). If lesions occur on young leaves that have not fully expanded, the leaves will distort as they mature. Plants will begin to drop infected leaves, resulting in a higher potential for sun scald on the fruit. Growers should consult the Pepper Section of the 2019 Commercial Vegetable Production Guide for suggested treatments, and maintain adequate fertility to the plants to encourage new canopy growth.
Pheromone traps established for beet armyworm (BAW) in the southern counties have begun catching adults. At this time, most activity is in the Woodstown (12/night) and Jones Island (10/night) areas, with low numbers also occurring near Folsom (5) and Pedricktown (2). This pest can reach levels that result in damage to pepper plants, although this does not occur each year. Growers in the southern counties should be alert for the appearance of severely defoliated terminals (see photo at left) on pepper plants. Small BAW larvae feed on these leaves before turning to fruit as they increase in size. As with FAW, beet armyworm is resistant to pyrethroid insecticides. Insecticides now recommended for CEW and FAW control are useful for BAW management.
Pumpkins and Winter Squash
Note that cucurbit downy mildew (CDM) was discovered on cucumber in Salem County., as per Dr. Andy Wyenandt’s Pest Alert of 7/4/19. Most races of this disease infect cucumber, and we experience CDM on this crop each year. Other cucurbits are at risk from specific strains. For this reason, we maintain sentinel plots of various cucurbits so that growers know which types are threatened. To date (7/17/19), CDM has not been reported on other cucurbit crops in NJ, and the sentinel plot now established at Snyder Farm in Hunterdon County ramains free of disease on all crop types. Nonetheless, all growers should be scouting for CDM on all cucurbit crops at this time. For regional information on this important disease, see the Cucurbit Downy Mildew Forecast webpage: http://cdm.ipmpipe.org/. This weeks’ forecast has NJ at moderate risk (Wednesday) of infection from sources to our south.
Cole Crops
Black rot, a bacterial infection, is occurring with more frequency on a variety of cole crops. Tuscan kale seems particularly susceptible to this disease. Black rot is characterized by yellow triangular lesions that form at leaf margins (see photo at left). As the disease progresses, the lesions move further into the leaf. Often, cabbage heads remain unaffected, as the lesions are confined to the older frame leaves. In collards and kale, however, this disease can be economically significant. While copper applications may help some, crop rotation and sanitation are key to avoiding black rot. Promptly incorporate old plant material into the soil, and avoid susceptible crops for 3-4 years if possible. Avoid working in infected fields when foliage is wet. If it is necessary to work in multiple fields, work from youngest to oldest plants to prevent spreading infections to young plants.
