Veg Weekly: ENYCHP Update 6/7/2023

All/multiple crops: Heat and drought stress observed in transplanted vegetables that have endured the harsh conditions of the last few weeks without rain, particularly on farms without reliable means for irrigation. Poor germination in unirrigated fields of direct seeded corn and other crops also prevalent in areas without rain.

Cutworm damage continues to be sporadic on seedlings in the field.

Most of the region has experienced poor air quality June 6-7 due to smoke from Canadian wildfires moving into NY. Excessive particulate matter can negatively impact plants, especially young transplants and plants otherwise stressed by drought or other abiotic factors, by reducing photosynthesis and interfering with stomatal functioning. Any visible damage will likely become apparent in about one week. Symptoms may look similar to ozone injury.

Alliums: Second flight (first 2023 generation) of leek moth expected soon, earlier than usual due to above average temperatures. Most leek moth damage to date has been observed in the northern part of the ENY region. If you suspect you have leek moth but are unsure, contact one of the ENYCHP vegetable specialists for diagnosis.

Onion thrips levels continue to be below threshold in most areas with the exception of some fields of transplanted onions in close proximity to where hay has been recently cut resulting in the migration of adult thrips out of the hay and into the onions. Growers who intend to use Movento or Senstar as part of their thrips management plan should remember that the products are most effective when applied twice consecutively 7-10 days apart BEFORE BULBS ARE 1” IN DIAMETER. Dr. Brian Nault and NYS Onion Specialist Christy Hoepting updated onion thrips management guidelines for 2023 that are available here.

Much of the region is either at peak onion maggot flight or 7-10 days past peak flight. Scout fields for onion plants that are wilting and carefully inspect the roots and basal plate for maggots.

Brassicas: Some cooler areas of Eastern NY are still finding cabbage maggots in brassicas. Research conducted in western NY has found that soil directed sprays of Radiant SC at 5-10 fl oz/acre reduced cabbage maggot by up to 50%. Organic growers who did not cover brassicas and are experiencing cabbage maggot pressure can apply a soil directed spray of Entrust SC at 5-10 fl oz/acre; see the label for specific directions on how to calculate application rates for cabbage maggot on page 51.

Cucurbits:Striped cucumber beetles are out and about in large numbers searching for hosts. Delayed growth in transplants set out prior to the May 18th freeze as plants continue to recover.  Transplants set out in last week’s heat on plastic mulches are showing symptoms of heat stress – many of the older leaves that were touching the plastic have turned either brown and are crispy or have just wilted away.  Take a look at the growing points and if they are green and growing the plants will be fine.  Areas that got some rain yesterday out of those thunderstorms, will help plants recover.

Nightshades:  As with cucurbits, tomatoes, peppers and eggplant that were set out in last week’s heat were also showing some heat stress, especially plants that were set too deep in the hole on plastic mulches and had part of the stem touching the sides of the plastic.  Plants may have a small girdle or pinching where the stem was touching the plastic.  More than likely those plants will not be as healthy or strong for the rest of the season compared to uninjured plants.  If you have extra plants, it’s probably a good idea to replace them.

Magnesium (Mg) deficiency is showing up in some tomatoes grown in high tunnels.  Mg deficiency symptoms are easily identified by the interveinal chlorotic mottling common on lowest leaves when the first fruit clusters begin sizing up.   Generally, Mg deficiency is not a major concern as long as the symptoms are limited to older growth.  Epsom salts and sul-po-mag are some sources of supplemental magnesium.  Often, growers will use Epsom Salts (magnesium sulfate) at a rate of ½ teaspoon/gal water) as a mist foliar application. Typically, it takes about 4 gallons to cover a full high tunnel.   Foliar applications can be used to correct small deficiencies in a single season, but soil applications are more appropriate for longer-term correction, but be careful as adding higher amounts of Mg than needed may trigger potassium deficiencies. Click here to learn more about high tunnel nutrient management.

Corn: European corn borers (E and Z strains) continue to be captured in low numbers in the region, but little damage is yet to be seen in the field.  Weeds also continue to be probably the most widespread problem being seen this week.  See the article from Cornell Weed Specialist Dr. Lynn Sosnoskie about herbicides and weather conditions and how they impact herbicide activity and weed control.  Impact/Armezon plus atrazine and nitrogen and either MSO or COC used post emergent should work well on most broadleaves and grasses.  See the longer article posted two weeks ago for more options and information.

Sweet Potatoes: See last week’s notes for more detailed information on slip handling and post-plant irrigation. It is common for slips to lose their foliage and appear desiccated after planting; continue to maintain adequate soil moisture and check slips after 3-4 days for initial root development from buried nodes.

Miscellaneous: Tarnished plant bug adults and nymphs seen feeding on cut flowers and strawberry flowers in north.