Vegetable Scouting Report: August 6, 2025

All/multiple crops: Tarnished plant bug populations are very high now and are causing damage on many crops. Keeping weed pressure low can help reduce habitat. Scout for both adults and nymphs (which look like speedy aphids) if you are seeing unexplained damage to crops. They can cause leaf distortion, stunting, and flower drop.

Wildfire smoke has been heavy this week around the region. These conditions are not likely to cause any meaningful harm to crops but may decrease photosynthesis when sunlight is reduced. See Dr. Steve Reiner’s 2023 article for more information.

Lack of rain over the last week and in the upcoming 10-day forecast will likely cause moisture stress in crops if not irrigated. Blossom end rot in fruiting crops has been seen around the region. Even and adequate moisture through irrigation is important to prevent this physiological disorder. Hot and dry conditions also favor two-spotted spider mites, seen on both high tunnel and field crops around the region in the last week. On the bright side, the dry weather has limited spread of serious plant diseases including late blight and cucurbit downy mildew, as leaves are staying dry and rainstorms are not spreading spores.

Alliums: In the north, the third flight of leek moth began last week. Onions that have not yet been harvested, leeks, and other alliums still in the field are susceptible to damage from caterpillars that will hatch in the upcoming weeks. Plants should be treated with insecticide at peak flight, likely occurring next week or the week after. Avoid bringing infested foliage into drying and storage areas, as caterpillars can bore into bulbs after harvest.

Brassicas: Despite the above-average temperatures, there are still some nice broccoli and cauliflower coming out of the Capital District now. Cauliflower in particular is showing tip burn, particularly in plantings that experienced any drought stress. Tip burn often shows up on the innermost leaves and may be hidden by the outer leaves until the head is exposed. If no other disease attacks these leaves, tip burn is cosmetic. It can be prevented to some extent by adequate moisture but can be hard to completely prevent during heat extremes.

Cucurbits:  A fair amount of virus has showed up this past week in vine crops across the region as we’ve seen slow increase in more aphids in vine crops the last couple of weeks.  Aphids are the main vectors or movers of viruses in many plants, especially vine crops.  The problem is, it’s almost too late once you see the aphids to stop the virus as it only takes a few seconds for the aphids to transmit the virus.  However, that does not mean that you shouldn’t try to control aphids not just to slow the transmission across the field, but for other reasons too such as preventing the sticky “honeydew” that they excrete onto fruit and potentially lowering the number of aphids that can spread the virus to certain perennial weeds that can overwinter the viruses. Beleaf and Fulfill are good to use when aphid populations are very low. Assail or Arvida are good options, especially if striped cucumber beetles and/or gray squash bugs are also in high enough populations to treat.  Timing of virus infections is critical in the impact that it will have. If viruses hit your crop early in its development, there can be yield and quality loss.  If it occurs after fruit set and sizing, the impact is usually less and yields and quality are usually fine.

Downy mildew continues to show up on new farms in the region in cucumbers, but has not yet been detected in the northern part of the ENY region.  Please make sure that when you are done harvesting a planting, destroy it either mechanically or chemically with a non-selective herbicide like paraquat or gramoxone. These old plantings if not destroyed will act as a reservoir of spore production for the rest of your cucumbers and other vine crops.

Legumes: On farms with virus issues in cucurbits (see above), you may also see these viruses showing up in other susceptible crops. Cucumber mosaic virus was seen this week in green beans—plants were stunted, yellow, and had crinkly leaves.

Nightshades:  Last week’s cooler nighttime temperatures finally kicked field plantings of tomatoes into ripening mode. Tomato ripening is quite dependent on temperatures with at least a 20 degree difference between nighttime and daytime temperatures. Two-spotted spider mites have flared up in some plantings so be sure to pay attention to newer growth and look for kind of a bronzing or speckled appearance to the newer leaves. Upon flipping them over, you might be able to see a spider webbing and with a hand lens or magnifying glass, the mites themselves which have two, brownish spots on their backs. There has also been a fair amount of blossom end rot, mostly related to water management. As plants become loaded with fruit, it is important to maintain optimum irrigation. This is best achieved with more frequent watering but with less duration. A couple hours a day on most soils is better then 6 hours every couple days. Once mulched beds get dry, it is very hard to get them moist again. Aphids have also been showing up in peppers the past couple of weeks so be sure to keep an eye on them and treat when populations are low. Beleaf and Fulfill are good options when levels are low and Assail/Arvida is a good choice when populations are higher.

There seems to be a lot of early potato dying, especially where fields were not irrigated or not irrigated enough.  The key now will be to manage the weeds in those fields until harvest.  This is where the materials labeled for vine desiccation can come in handy. For a list of vine desiccants, click here.   And don’t forget when you’re digging potatoes for market now – do not put “hot” potatoes in wash water that is more than 10 degrees colder than the potato pulp temperature.  When you put the potatoes in this water, it will act almost as a vacuum and the wash water can be pulled into the potato. This dirty water can contain soft rot organisms and other pathogens that can impact crop quality. Make sure they are dry to before packing them, especially in plastic bags or containers.

There have been no new reports of late blight spread to eastern NY as of now. Elizabeth Buck and Margie Lund from the Cornell Vegetable Program wrote up a great article on control strategies, which can be found here. Make sure that you are applying protectant fungicides to all tomato crops and either protect or terminate potatoes to prevent tuber infection. A complete table of available fungicides can be found here.

Sweet corn:  Western bean cutworm moths are out in force and larvae could be found in younger pre-tassel sweet corn. This is the stage corn that WBC is most attracted to so be sure these state fields for egg masses and larvae. After tasseling, larvae will make their way to the ears. The threshold in fresh market sweet corn is 1%. It is critical that sprays are timed before the larvae have a chance to enter the ear. The good news is that corn earworm counts have come down a bit across most of the region with many areas calling for a 5-6 day spray schedule in green silking corn.

Fall armyworm pressure is increasing in the north, with moths captured in traps for the first time this week. See last week’s scouting report for more information.

Miscellaneous: Please let us know if you have basil downy mildew on your farm. Researchers at Rutgers University are collecting samples from around the U.S. and Canada to better understand this pathogen. For more information on this serious disease, see Dr. Meg McGrath’s basil downy mildew website here.