Rhode Island Apple IPM
May 4, 2010: Recorded Apple Pest Message in Print

May 4, 2010
This has been quite a week. I haven’t talked to growers but I think several applied a streptomycin spray protecting against fire blight in susceptible, blooming varieties. I think that most orchards are past bloom now and therefore not susceptible to fire blight infections. If there are still open flower blossoms in your orchard, there is still the potential for fire blight infections this week. Fire blight needs warm temperatures and rain or heavy dew in the presence of open flowers. If applying strep, it must be sprayed within 24 hours before or after the rain.

We are getting near the end of primary apple scab season, but we are there yet. Keep your trees protected with fungicide.

I’ve heard reports of plum curculio scars in neighboring states. Warm, humid weather this week is perfect for plum curculio activity and some varieties have fruit large enough for plum curculio to scar (7 mm). If you have not applied a petal fall insecticide yet, do it soon. By the weekend temperatures are predicted to cool off. This will slow down plum curculio but a lot of damage can happen before the cool down. Insecticides effective against plum curculio include Imidan, Actara, Avaunt, and Calypso.

I’ve seen some egglaying of European apple sawfly near the calyx end of small developing fruit. Petal fall insecticide applications will control this pest as well.

I intend to visit several orchards tomorrow and will give a more informed message on Wednesday, May 5th