Horticulture Guy

Pest Alert

  • Apple Maggot larvae have been in the dormant pupae stage over the winter and are in the process this month of emerging from the ground as adult flies. The Adults superficially resemble houseflies and are about 1/4 inch long. They have a black and white banded pattern on the wings and a white spot on the body. They have many hosts but apples, crabapples and hawthorns are the most common in the PNW but sometimes they can be found on plums, apricots, pears, Asian pears, Sweet and sour cherrries, rose hips, cotoneaster, mountain ash and pyracantha. Monitor and control with Apple maggot traps and lures. They do not emerge all at once but instead emerge in waves throughout the summer until early fall. There is an organic spray made from kaolin clay (used in the food industry for its anti caking effect) and sometimes goes by the trade name Surround WP Crop Protectant. You can also control the adults using either the sticky apple traps or the yellow sticky traps in conjunction with apple maggot lures. None of these controls are 100 percent effective so I always suggest protecting some of the fruit with plastic bags. Tie them around the fruit to prevent the flies entry. Be sure to leave enough room for developing fruit. This is an insurance policy for some larvae free eggs. The first line of defense starts in the fall when you should lay out tarps under the trees to prevent infected apples from reaching the ground and releasing the larvae. Another option is to use a specific species (Steinernema feltiae ) of beneficial nematode which is sometimes found under the trade name Scanmask has been found effective for control of larvae in the soil. These beneficial nematodes are available online and sometimes can be ordered through garden centers.
  • Spittle bugs - foamy masses found on your strawberries, peas or flowering plants and herbs are the protective coating of small sap sucking insects. They are easy to control with a strong blast of water which breaks up the foam and knocks the insects from the plants.
  • Cabbage loopers (cabbage worms) - If you have seen the pretty little white butterflies hovering over you cole crops like broccoli, cabbage and cauliflower you should be on the lookout for the eggs that it deposits on the underside of the leaves. Left unchecked they will hatch into hungry caterpillars that will chew holes in the foliage and into the florets of the broccoli and cauliflower. Control by rubbing eggs off of the foliage and then by using BT DIPEL 150 DUST.
  • Carrot rust flies - this quarter inch fly with yellow legs and yellow head is seldom recognized or seen by gardeners. But after they lay their eggs at the base of the carrot the damage of the white maggots is very evident. If you have this pest the best control is growing carrots under a floating row cover (Remay) to prevent the fly from laying its eggs.
  • Aphids - This sap sucking insect has been around since earlier in the spring and may have gone unnoticed until now. The populations in June increase dramatically and can be green, red, black and yellow in color. Use insecticidal soap, APHID CHASERS or APHID & WHITEFLY STICKY YELLOW TRAPS to control them.
  • Slugs - continue to be a nuisance particularly in shady parts of the garden. Use organic bait products with iron phosphate like Sluggo.
  • Rhododendron Lace Bugs - The “lace” of the adult insect’s wings can only be seen under a microscope since the adults are only about 1/8 of an inch long. What are usually most visible on the underside of the leaves are the insect’s excrement and the nymph’s shed exoskeletons, which are shed at each stage of growth. Symptom include yellow to brown speckling on the surface of the leaves and activity below the leaves where the lacebugs and their juvenile nymphs are feeding. They feed like aphids with piercing sucking mouthparts. Often a large infestation of Rhododendron Lace Bug is a sign that the rhododendron may be under some stress. Sometimes infestations are exacerbated by drought, to high a pH (they prefer to be somewhere between 4.5 to 6.0) or too much direct sun. Both insecticidal soap and neem oil will control Lace Bugs. Or you can use the best of both worlds and use a new neem soap, which is derried from the neem oil,
  • Beneficials - Benefical insects are also emerging now since lagging slightly behind their prey. In particular Lady bugs and their alligator looking offspring have appeared. Be very careful since the black (often with orange spots) lady bug larvae are often unfamiliar to many gardeners and are often sprayed as pests. The young eat even more aphids and soft bodied pests than the adults do. You can help attract and keep aphids in your garden with LADY BUG HOUSE and LADY BUG LURES Hover flies (Syrphid Flies) have black bodies with yellow bands much like a bee. The adults can be seen hovering around flowers and feeding on the nectar and pollen. Their larvae have small fangs that feed on soft-bodied insects like aphids.
  • Wasps hornets and yellow jackets : Increase activity and nest building begins in June. These insects are beneficial preying on many garden pests. They can be a problem when nests are too close to human activity.Poison Free Wasp and Hornet Killer is an organic control in these situations.