Very small gypsy moth larvae have been picked up over the past week. Since the weather has been cool and wet, numbers are off a bit of where we typically are. Whenever there is a sunny calm day, be sure to make some sweeps. If weevil is not in the mix, Delegate is a good choice for the cutworm pests, as is Intrepid. Sevin can also be a good choice if your caterpillars are dominated by gypsy moths. Cranberry weevil are being swept now; the threshold is 4.5/25 sweeps. Grey weevils found in the sweeps should not be counted as they are not a cranberry pest. Avaunt is good against the spring populations, with a max of 2 applications prior to bloom allowed. Do not use after bloom. Actara is effective against spring and summer generations of weevil but is Restricted Use and Zone 2 restricted. It is very toxic to bees and should not be used within 5 days of bee arrival.
Dodder has definitely emerged and if you can use QuinStar, we are approaching the window for early postemergence applications. Late applications of low rates of Casoron can go out now if you know your vines are not sensitive to the herbicide. Kerb is also available via an Emergency Exemption. Be sure to check with your handler prior to using Kerb or QuinStar. Two applications of Kerb are permitted, not to exceed 5 pt/A. It is expensive, falling in around $75/A at 2.5 pt/A rate. Any escaped dodder can be targeted with concentrated sprays of Callisto in June and July.
Be sure to round up your pheromone traps, stakes, and bait to put your traps out by June 1. First fertilizers go out around roughneck to hook, applying up to 20% of your total N. If you are using only slow-released or controlled-release, it goes out now! If you don’t use 100% SR or CR, apply the remainder at set as fast-acting sources.
Coastal Plymouth County bogs should have the LW flood removed around May 20 and Cape bogs should pull water in late May. Remember that the frost tolerance will be 29.5 F as soon as the flood is removed, no matter what the buds look like. You still need to scout your LW bogs for early spring insects, even though you will likely be able to omit the early insecticides. Cranberry weevil is NOT impacted by LW and may need management depending on what numbers you pick up. Nitrogen needs for the vines are usually less on LW bogs, so you can usually skip your first N application and/or reducing the fruit set dose. It is best to wait at least 2 weeks after flood removal and add small amounts and monitor the progress of growth. Generally, no fertilizer is needed before bloom, but go out and look.
We will be holding a bogside workshop on Wednesday May 29 at 10 AM. We’ll meet under the oaks unless the weather is bad, then we’ll be in the library. 1-2 contact hours will be offered.