Between the end of May and first 10 days of June, getting trials planted has been challenging with showers just about every 3 days. Typical field work ahead of direct seeding or transplanting (tillage or burn down) into our research and demonstration plots at South Charleston was definitely a “hurry up to wait” scenario. Hopefully most of you are having better luck at getting these crops in the ground!
As soon as I did manage to get some seeds and plants in the ground, there were quite a few pests waiting to pounce; read on and find out who!
Striped cucumber beetle – This is a pest that we expect to find every season. While it was reported several weeks ago in Southern Ohio, it made an appearance this past week in South Charleston. Notice the characteristic feeding damage on the lower cotyledon surface and on some of the early leaves. If FarMore FI400 seed was used not much damage should be expected but for untreated plants, scouting every few days while seedlings is important, followed by foliar sprays if beetles go over threshold (0.5 – 1 beetle / plant). Foliar insecticide options for all pests can be found in the Midwest Vegetable Production Guide (https://mwveguide.org/guide).
Salt Marsh caterpillar – A sporadic pest that is primarily a foliage feeder. While feeding can be fairly severe, typically very few plants are affected. The injury looks similar to that of striped cucumber beetle feeding shown above.
Black cutworm – Another sporadic pest found especially in no-till fields where winter annuals such as chickweed and other weeds are present during seeding or transplanting. If a burndown herbicide is applied or other disturbance to the field is made, these caterpillars will move to and feed on fresh plants, including pumpkin or squash seedlings. The damage is characteristic cutting of the stem at the soil line and often the cut stem and leaves will be pulled into the soil. To find the cutworm caterpillar, lightly dig around the cut plant to find and destroy the pest or risk other seedlings being cut.
Field mice and voles – In reduced tillage situations or fields planted with cover crops, there is an increased risk of depredation by several species of mice and voles which can feed on a variety of plant parts including leaves, stems, roots and seeds of plants. They have a particular fondness for pumpkin and squash seed, and can move down a planted row systematically digging up and eating every seed for stretches up to 50 feet. Even newly emerged seedlings aren’t safe from feeding as the cotyledons and radical (main root) can be chewed off, killing the plant.
In every direct seeded trial at the research station this year, we have lost between 30 to 95% of stand due to seed feeding, so this is a major consideration for us to decide if a trial gets direct seeded or transplanted. For growers, the size of the operation and effort to raise transplant needs to be evaluated against the expense and time lost to replanting (7-10 days) which can affect marketing and field harvest, possibly impacting sales.
There are a few ways to minimize mouse and vole seed and seedling depredation including increasing field tillage to disturb nesting areas, reducing the rate of cover crop planted to provide less cover for these vertebrates and providing perching structures near the field to invite raptors to prey on these pests. Planting in warm soils will promote faster germination and limit the time seed is vulnerable to depredation.
The only approved chemical treatment is an in-furrow application of zinc phosphide pellets. This is a Restricted Use Product and is not allowed to be broadcast on the field.