Apple Pest Management Trial

Mr. Lego wanted to reduce the amount of pesticide he uses on his apples. He obtained a SEED grant to implement established IPM practice on his apple orchard, and to investigate an alternative method for trapping apple maggot adults.

Mr. Lego’s comprehensive plan for pest control involved extensive monitoring for disease and insect thresholds. He applied his sprays (Dipel for oblique banded leafroller, Nova, a sterol inhibitor, for apple scab, Imidan for plum curculio and codling moth) according to IPM-recommended thresholds and accumulated degree days, which added up quickly as summer came early in 1998. He attempted to control apple maggot by trapping out the adult phase, and for this purpose experimented with apples as bait, and compared this with commercially available red sphere traps.

Results

Apple scab: Mr. Lego gave four applications of Nova to his non-apple scab resistant trees between April 6 and June 12. Wettable sulfur was included in the final two sprays. Resistant varieties (Liberty, Redfree, Pricilla, Macfree, and others) were not sprayed, and displayed no evidence of apple scab. The non-resistant varieties did suffer from apple scab, the Empress, Empire, Smokehouse, and Fuji trees displaying the worst infestations. A serendipitous finding was that certain heirloom varieties—Cox Orange Pippin, Spitzenberg, and Winter Banana—appeared to have some resistance to scab.

Apple maggot: The trapping strategy succeeded at keeping the incidence of apple maggot to an acceptable level. Real red apples, until they began to rot, were as effective for baiting as commercial red sphere traps, and were cheaper and easier to handle.

Plum curculio and codling moth: These were effectively controlled with four applications of Imidan between May 11 and June 12.

Mites: Neither the European red mite nor the two-spotted mite was observed, possibly because of a single prophylactic application of Sunspray oil on April 1. Beneficial mites were, however, observed.

Oblique banded leafroller: Young trees were sprayed three times with Dipel during June and early July, which effectively controlled this pest.

European sawfly: This is not supposed to be a problem in Mr. Lego’s area, but his orchard suffered a serious infestation of this pest in 1998. He was unprepared for it, and took no measures against it.

As part of this project Mr. Lego prepared an instructional program on apple IPM, a copy of which he submitted with the final report. He has delivered this program to other orchardists interested in IPM.