All/multiple crops
Tarnished plant bug (TPB), A.K.A. Lygus bug, feeding damage has been noted in the past week. In lettuce, brown, sunken scars appear along the ribs and is especially noticeable in romaine. In tomatoes, eggplants and peppers, feeding often occurs on new growth especially on flowers and buds which can cause flower drop and leaf browning or distortion in peppers and basil. Direct feeding on growing fruits results in dimpling and light-yellow spotting on mature fruit. TPB often move into crops when nearby alfalfa fields are cut. It is easy to miss TPB as they quickly move away or hide when disturbed. Weed control around vegetables will help limit populations from building in crops. A number of synthetic Pyrethroids are labeled for TPB management. Organic growers can use Pyganic. Read label instructions carefully to minimize risk to pollinators.
Alliums:
Most garlic is either harvested or being harvested now. A reminder to dry garlic in as warm and dry a space as you can, up to about 110 degrees F. The faster you dry garlic and then move it to a climate-controlled storage area, the less risk you have of post-harvest diseases such as botrytis neck rot and black mold becoming a problem. If you are running short on space in the drying area, remember that research indicates that removing the tops of garlic does not affect the final dry weight or storage quality, and reduces the amount of green material in the drying area dramatically.
Caterpillars from the second flight of leek moth are now active in onions and other alliums in the north. Trap catches have been low and perhaps unreliable this year, for unknown reasons. UVM Extension has also reported low trap catches in Vermont. Research in VT has shown that onions can be topped before curing to remove leek moth caterpillars at harvest, preventing damage to bulbs in storage without consequence to storage quality and longevity.
Despite repeated rain events, high numbers of thrips continue to be found on onions in the north. Wet conditions are promoting purple blotch and stemphylium infections.
Brassicas:
Low levels of swede midge damage are evident around the north. To protect fall brassicas, transplant away from previously infested fields and treat transplants with systemic insecticides, such as neonicotinoids. On organic farms, insect exclusion netting is a reliable control measure, as long as crops are planted on uninfested ground. For more information on swede midge management, see the following fact sheets: NEW Crop Rotation Recommendations for Swede Midge and Organic Management of Swede Midge.
Cucurbits:
Cucurbit downy mildew continues to spread across the North Country, now found in St Lawrence and Essex Counties in the past week. Conditions are exacerbated with frequent rainy days, and symptoms have also been observed in high tunnel cucumbers. Growers should continue to protect their cucumber and melon plantings with regular fungicide applications.
Other parts of the region including the Capital District and Hudson Valley have not reported additional downy mildew outbreaks, but growers in all parts of the region should remain on a preventative spray schedule since spores can move readily in storms.
Wet weather has also promoted infection by other cucurbit foliar diseases, and we have been seeing many causes of angular and Alternaria leaf spots as well.
Nightshades:
Tomatoes in full fruit are showing more early blight, a sign of stress in the plant. This is a good time to complete a foliar test on plants in order to ensure that you are providing sufficient nutrition to allow them to complete the season. We use Waters Ag Lab for most of our sampling, though we don’t recommend it specifically. If taking a sample, select 10 of the most recently fully expanded leaves and wash them with clean water if they have been sprayed with nutrients or copper. Let them air dry, place them in a paper bag with the sample form, and you’ll get results back in about a week, depending on when in the week you mail your sample.
In addition to early blight, leaf mold and septoria have been observed in high tunnel and field tomatoes. We continue to monitor the spread of late blight, which was confirmed recently in Ontario, Canada.
Hornworms are now active in the north, and should be treated while small for pesticide efficacy and minimal damage to plants.
Corn Trap Counts
Very large numbers of western bean cutworm were found in traps this week in the north. Scout corn for egg masses, which turn from cream/white to dark purple before hatching. Treat corn when 1 egg mass/100 plants is found. Additionally, sporadic fall armyworm damage in corn has been found despite no trap catches in the north. Scouting for caterpillars is the most reliable method to monitor for fall armyworm to determine when to spray.
