Please see the section on "Conidia Suppression" on pages 17-18 of the 2000-2001 New England Apple Pest Management Guide for fungicide options to suppress conidia production.

Cedar Apple Rust (CAR)-- Again, with the frequent rains we had in May, it is not surprising to see the numerous CAR lesions on foliage. Peak release of spores from cedar galls to apple trees occurs from early pink to full bloom. Through mid-June, additional foliar infections can occur in orchards; however, the fruit is resistant to infection after petal fall. There is no additional spread (i.e., secondary infections) of the disease in the orchard. EBDC and SI fungicides used during spore release should have provided some protection against this disease.

Fire Blight: If fire blight infection did occur, the Maryblyt model predicts that blossom blight symptoms should appear after 103 Degree Days (base 55F) have accumulated from the date of infection. Using estimated temperatures for the two sites (Bennington, Saxtons River) where the model predicted conditions were favorable for infection, 103 DD had accumulated by May 25 in Bennington; in Saxtons River, it is predicted that 103 DD will be reached by June 7.

Hopefully, we will not see any blossom blight symptoms in Vermont this year. So far, none have been reported. The Maryblyt model assumes inoculum is present in the orchard and in many cases, it may not be. For example, Dave Rosenberger, the plant pathologist in the Hudson Valley, recently noted that although conditions were very favorable for blossom blight infection over a six day period during bloom, relatively few farms in the Hudson Valley have reported fire blight symptoms and only a small portion of the total Hudson Valley apple acreage was sprayed with streptomycin at bloom. Currently, we lack a good method of determining the presence of fire blight inoculum in an orchard at bloom.

                   TPB population and damage below ''normal"

                    EAS population and damage below "normal"

                    Plum Curculio damage light so far

At the UVM Hort Research Center we also have been tracking DD (base 50) from May 15, which was the first CM pheromone trap capture (the biofix). As of June 4, we have accumulated 156 DD. In orchards were CM is a chronic problem and pressure is significant, a spray applied at 250 DD, corresponding with predicted 3% egg hatch, and then another spray 10-14 days later should be effective (see following information on 'reduced-risk' insecticides for modification on timing initial spray). In moderate pest pressure, one spray at 360 DD after the biofix may be sufficient. The following is from an article written by H.Reissig, Cornell Entomologist, that appeared in a recent issue of Scaffolds: "Insecticide trials conducted in N.Y. over a number of years in research orchards heavily infested with CM and other species of internal Lepidoptera have shown that most currently available IPM-compatible, "reduced risk" insecticides (Comply, Dipel, Confirm, and SpinTor) are slightly less effective in preventing fruit injury than are standard organophosphate insecticides, such as Guthion and Imidan. However, it is likely that these selective materials applied on a schedule of 2-3 sprays/generation of CM, based on predictions from a CM developmental model, will provide adequate control in normal commercial apple orchards that are not located adjacent to abandoned orchards or extensive acreages of feral, unsprayed apple trees. However, since some of these materials have limited contact activity against young CM larvae, and are only effective when ingested, they may be more effective if they are applied 5-7 days earlier than the estimated first hatching date predicted by the developmental model for each generation of CM. This type of scheduling ensures that eggs are deposited on residues of the material so that hatching larvae are more likely to ingest a lethal dosage of the compounds before entering the fruit. "

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