Rhode Island Apple IPM

June 4, 2009 Recorded Pest Message in Print

I’d be happier if the wet weather would cease for a while and let everything dry out. Sounds like we get a soaking rain on Friday, June 5. According to Orchard Radar, because we are expecting more than 2 inches of rain on Friday, this means another insecticide may be needed to control plum curculio after the rain. I think this may be too conservative for orchards away from the coast. I think non-coastal orchards will not need another insecticide spray to control plum curculio. It does make sense to scout your orchard for new plum curculio scars. Especially check smaller, later fruit that will be more attractive to plum curculio now. Look for the small, mushroom-shaped plum curculio scars. New scars are relatively smooth on the fruit surface and often have an orange tinge along the edge of the egglaying scar. Orchards close to the coast are further behind and may require another insecticide application regardless of Friday’s weather. See Orchard Radar at http://www.uri.edu/research/ipm/

If you see several leafminer mines now, don’t bother spraying for them now. It is too late to control the first generation mines. If you are finding 2 or more mines on all the leaves surrounding a fruit cluster, consider spraying for the next generation of mines. The timing to spray the second generation is around early to mid July. Effective insecticides include Provado, Assail and Calypso.

Hopefully everyone has thoroughly scouted his orchard for apple scab. If you can’t find scab, or only one or two lesions, you can extend the time between fungicides to 2 weeks. While we are still receiving so much wet weather, it does not seem appropriate to go 3 weeks between applications. If you are finding scab, apply a full rate of Captan and repeat in 7 days. It takes approximately 3 weeks for scab lesions to die. During that 3 week window you must keep the fruit and foliage well protected with Captan.

Continue to scout for mites. This wet, cool weather should be keeping mite numbers low. I don’t anticipate anyone spraying for mites now.

We will have our third and final Twilight meeting on June 18 – but I don’t know where. I’ll let you know as soon as I do.