When should I spray my honeysuckle bush for aphids?
For the last two years, we have had very bad aphids on our honeysuckle bushes. We were thinking of using a neem oil this year. Can we spray the tree now (mid-March) when it's just starting to leaf, or wait until the aphids infest?
Boulder County Colorado
Honeysuckle aphids have several generations a year, so repeat applications of the horticultural oil will be required to keep them under control. They overwinter as eggs on the ends of shoots or on leaves. You can prune out infested ends of stems where overwintering eggs are found in early March. Make sure to seal the cuttings up in a plastic trash bag.
In late spring before the plants leaf out, apply horticultural oil as a dormant treatment. The oil will suffocate a lot of the eggs. Check the plant regularly through the growing season and reapply horticultural oil on the plant (make sure to read the label for proper use in summer months - e.g., rate of application and temperatures not to apply). The oil works on contact with the aphids, so be sure to spray all sides of the leaves including under the leaves where initial colonies develop.
Avoid applying horticultural oil to drought-stressed plants. You could water your honeysuckle the night before applying the horticultural oil as it is not good to apply oil to a drought-stressed plant. If the temperatures are too hot (90+ degrees), you might want to alternatively try spraying the plant with water if you see an infestation or cut out damaged leaves. Remember to read the label.
Here is a link to some information on horticultural oils: Insect Control: Horticultural Oils