Back to top

IPM Message for Cranberry Growers: May 28, 2015

May 28, 2015

Many growers have been treating with Avaunt over the past few weeks for winter moth or weevil. Winter moth should be finishing up so it's is time to stop chasing. Weevil has been reported over threshold and it should be treated if you have high numbers. Spag is out and larvae are getting picked up in sweep nets now. We had also heard of high counts (8 larvae) of black-headed fireworm. Marty also reports seeing some weird spanworms out there, but nothing to be worried about. If you are using pheromone traps to time sprays for BHF, Spag or girdler, traps should be out by June 1. Use 1 trap per 10 acres and place them on the upwind side of the bog so that the pheromone blows across your bog. Check them weekly (more or less depending on flight patterns) and clean or change them as needed.

I have had a couple of questions about treating for control of poison ivy. Spot-applications of concentrated rates of Callisto with either COC or NIS give good control. Our 2-year trial showed better control in Year 1 when we treated mid-June/early July compared to late May/mid-June applications, but both decreased PI and cranberry growth rebounded. The difference between the two timings became much smaller in the second year when we treated in 2 consecutive years. The bottom line is if you have poison ivy in spots and have time to treat it, go for it. Two applications per year are recommended and they must be separated by at least 14 days. Use up to 1.5 oz/gallon with either NIS or COC, but if it is looking to be hot and/or you have flowers out there, I would favor the NIS. We have been working with Syngenta and we should have a Special Local Needs label for spot-treatments very shortly.

Early hybrids such as the Mullacas, were in hook stage earlier this week. So, for the very early varieties, first fungicide is just around the corner. 

We will be having a bogside workshop here on June 9 from 8-10 AM with 2 contact hours offered.