Pest Alert
Continued vigilance is necessary on slugs and aphids, which appeared last month. Both can reproduce without having to find a mate so their populations can build quickly. Aphid females can lay fertile eggs without the benefit of male input (called oogenesis) and slugs, like snails are hermaphroditic enabling them to fertilize their own eggs. Use a natural slug bait to control slugs. To control peach tree aphids on roses and other plants use the aphid chaser. On other plants you can use yellow sticky traps or spray the aphids with a neem based insecticidal soap.
Later in the month you may see Tent caterpillars. The population of this moth can fluctuate over a 3-10 year cycle. The tell tale sign is the large tent like silk web spun by the caterpillars as they feed on trees and shrubs. The caterpillars hide in the tent during the day and feed at night. The eggs started hatching out later in the month and so it is the best time to control them before they damage plants. Tent caterpillars will head down to the ground to pupate in July. The adult yellow-brown moths emerge next spring and lay eggs for next years generation. The first line of defense is physical removal of the nests. The best time to catch the caterpillars in the nest is when they are not feeding from dusk to a few hours past dawn. Soak the tent, caterpillars an all in a jar of rubbing alcohol. The second line of defense is to use a highly selective insecticide that won’t hurt potential predators. Spray trees and shrubs with Bt (Bacillus thuringiensis var. kurstaki). If you can reach put the spray nozzle inside the tent as well. The caterpillars must ingest the spray that coats the plants leaves. Another good organic control when the tree or shrub is not blooming is neem oil. In addition to spraying it is a good idea to apply sticky tree bands (on single trunk trees) that will catch any remaining caterpillars as they move down to the soil to pupate