All/multiple crops:

Intense heat, sun, and humidity this week are certainly a break from all the rain we’ve had this season. We hope that this stretch of weather will promote ripening in crops where development was delayed due to cooler weather earlier this summer.

 Alliums: 

Leek moth damage from caterpillar offspring of the third flight adults is now visible in leeks, chives, scallions, and onions still out in the field. Overall pressure has been low across the Northeast this season. Leeks are at highest risk this time of year as garlic and onions have been harvested already.

Allium leafminer (ALM) activity was detected today (9/7) in the Hudson Valley. Beginning in 2017, ALM emergence has been carefully detected and recorded for the Hudson Valley and has occurred between September 3 and September 19. Generally, emergence occurs a little later on farms north of the Hudson Valley. Growers with susceptible alliums such as scallion, chives, and leeks should cover these crops immediately with insect netting or row cover making sure there are no gaps along the edges. For larger plantings or other situations where row cover is not practical, there are effective OMRI listed and conventional insecticides that can be used to manage damage from ALM. See last week’s veg blog for more details.

Brassicas:

Diamond back moth dominated this week’s pests in brassicas. With this week’s heat and warmer nights, this moth can lay lots of eggs and produce lots of larvae within a short period of time, and seems to get harder to control as we get later into the season. And more bad news – reports out of New Jersey indicate that our go to conventional insecticides containing chlorantraniliprole (Coragen, Besiege) appear to be less effective in controlling this pest. In other words, make sure to include insecticides like Radiant (spinosyns or Group 5) or Group 6 (Proclaim). Scout often, especially within a couple days of treating to make sure you are getting good control of the larvae – if not, you need to re-examine your spray program and treat again.

We haven’t talked a lot about this disease, especially with all the rain throughout July and August, but Alternaria leaf spot is showing up. Lesions start out as small black spots only to enlarge to from target-like spots on leaves and petioles. Not only is the disease itself an issue, but the lesions can also serve as areas for bacterial soft rots and other diseases to get started, especially in broccoli and cauliflower. Chlorothalonil (Bravo, Praiz etc,) continues to provide good control if applied before the disease gets started. Other labeled products include Luna Flex and Sensation, Endura, Switch and others. Oso (polyoxin D zinc salt) is the most effective option for organic growers and has provided a similar level of disease suppression to chlorothalonil in trials in Western NY. Please review the labels for rates, PHI and REI’s.

Chenopods (Beets, Chard, Spinach):

Beet Armyworm: Reports out of New Jersey this week indicate high captures of beet armyworm (BAW). Don’t let the name fool you into thinking that this pest only infests beets – it has a wide host range including, but not limited to asparagus (also known as the asparagus fern caterpillar), bean, beet, broccoli, cabbage, cauliflower, celery, chickpea, corn, cowpea, eggplant, lettuce, onion, pea, pepper, potato, radish, spinach, sweet potato, tomato, and turnip. Larvae are very eager feeders and can defoliate plants very quickly but can also feed on fruit such as peppers. Unfortunately, BAW is resistant to pyrethroid insecticides (Warrior etc.), so other insecticides including products in Group 5 (Radiant, Entrust) or Group 28 (Coragen etc.) can be used.

Leafminer activity is also increasing in our region.

 Cucurbits:

Lots of calls coming into specialists in the last couple weeks from growers concerned about their fall crop yields. Delayed fruit set and ripening, poor weed control, disease, and other issues due to prolonged cool and rainy weather are creating a pumpkin shortage in ENY this season. Fruit continue to ripen on the vine and harvests may be later this year. This is not to say that yields are low everywhere – in fact there are some very good yields in some areas. The drought many of us suffered through in late May/early June had an impact on herbicide activity, germination and overall plant stress. Follow that in many regions by heavy and persistent rains in late July and August again impacted growth and increased loss from diseases like Phytophthora capsici. Add in the days when regions were blanketed by hazy conditions due to wildfire smoke and there is a very good recipe for low yields. Cucurbits, especially pumpkins, will not pollinate when conditions are not prime. During times of high temperatures, bees, especially honey bees will remain close to the hive, helping to keep the hive cool. They will also drop flowers when light conditions are not optimal like those experienced during the wildfire smoke warnings. Shading as with dense canopy can also cause flowers to drop.

From our colleagues in Michiagan, “Temperatures over 85 and below 50 halt pollination from honey bees, but squash bees and bumble bees will continue working beyond those temperatures if you have local populations. However, higher temperatures cause plants to close their flowers early even if pollinators are operating. Rain will also damper pollination, and again the honey bees are the first to quit, while squash bees and bumble bees will fly through low to medium levels of precipitation if you have them.” (Source: Michigan vegetable crop report – September 6, 2023).

Nightshades: 

Rain and cool weather earlier this season are causing physiological deformities in field tomatoes and peppers. Radial and concentric cracking and rain check in tomato fruit are common. Many peppers on plants are short and small due to cool nights that occurred before the heat wave this week, particularly in the north.

 Sweet Corn:

We continue to see fall armyworm (FAW) caterpillars and damage in the field despite low or no trap captures of FAW moths. The flight of western bean cutworm is now over in most of the region. Some areas are also experiencing large numbers of European corn borer.

More concerning is the number of corn earworms that are being captured, which actually shouldn’t be surprising seeing as we are in September and is when we tend to see some of the highest moth counts. Please be sure to cover with good insecticide sprays anything with green silk. Most areas should be on a 4-5 day spray schedule according to the trap catches.  Remember, in the heat experienced early this week, pyrethroids are very, very short lived so follow-up will be critical for good control.

 

Miscellaneous: 

The second edition of the Strawberry Production Guide for the Northeast, Midwest, and Eastern Canada is now available online! The guide was updated from the 1998 first edition by ENYCHP specialists Elisabeth Hodgdon and Laura McDermott and other collaborators under the leadership of Becky Sideman at UNH. The guide revisions were part of a SARE grant and include many updates on new pest and disease information, production practices, digital marketing, food safety, and more.