Developing pest management guidelines for organic production of highbush blueberries in the North Central Region

Developing pest management guidelines for organic production of highbush blueberries in the North Central Region

Summary

Objectives/Performance Targets

Accomplishments/Milestones

During fall 2009, bushes in the nutrition part of the organic blueberry planting were assessed for insect infestation. The main sources of infestation observed were the blueberry leafminer, Caloptilia porphyretica, and feeding from Japanese beetle, Popillia japonica. To assess their abundance in the different plots, three bushes per sub-plot were sampled, and the number of leaves infested with leafminer or damaged by Japanese beetle were counted. The number per sub-plot was averaged across the three bushes, and these counts were compared among cover crops and fertilization regimes using a two-way ANOVA.

Foliar feeding insects were not observed at a significantly higher frequency in any of the three nutrient management treatments. Blueberry leafminer and Japanese beetle abundance was variable across the planting, with some bushes having low infestation, whereas others had high levels, especially of the leafminer. Despite this, there was no significant difference among any of the treatments. Leafminer infestation was numerically higher in the compost blend treatment than the other treatments but there was no significant difference among these three treatments (P = 0.09). Low levels of infestation by Japanese beetles were observed at this planting, with an average of 2–3 injured leaves per bush and observations of higher leaf feeding at the edges of the planting. There was no significant difference among cover crops or among fertilization treatments in the level of Japanese beetle feeding injury. The numerically higher number of leafminers detected on blueberries fertilized with compost blend suggests that the leafminers may do better on plants with higher leaf nitrogen levels. The lack of observable differences in Japanese beetle feeding was not overly surprising given the small size of the experimental plots and the insect’s extremely mobile nature.

Impacts and Contributions/Outcomes

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