Insect Problems to Look For

Lace bugs on Azaleas and Rhododendrons I have noticed a lot of lace bug damage recently on azaleas and rhododendrons. Azalea lace bug attacks both azaleas and rhododendrons and may cause significant damage on both. Both adults and nymphs feed on the underside of leaves. Symptoms of damage are stippling, bleaching, or a silvery or yellowish (chlorotic) appearance of the leaves. The underside of the leaf will appear dirty due to the presence of brownish or tar-like fecal spots, particularly along the leaf veins. Several insecticides will control lace bugs. The problem is getting the bottoms of all the leaves thoroughly covered. Because of this, systemic insecticides which are translocated through the plant’s circulation system are most effective. Imidacloprid is a systemic pesticide which can be applied to the soil and is taken up by the roots. It is available in several brands including Monterey Once A Year Insect Control and Bonide Systemic Insect Control granules. Acephate (Orthene) is another systemic available in both spray and granular form. Spinosad is a new systemic organic pesticide which is effective on a wide range of insects. It is available as Ferti-lome Borer, Bagworm, Caterpillar and Leafminer Spray or Monterey LG6135 Garden Insect Spray. Neem oil is another organic pesticide which will control lace bugs.

Fruit Tree Spraying It is time to begin spraying fruit trees for diseases and insects as soon as the flower petals have fallen. I like to spray all fruit trees with a natural copper fungicide to catch the new leaves as they appear. This is critical for peach and nectarine trees to prevent peach leaf curl disease. It is also important for apples and pears to prevent scab disease on leaves and fruit. I combine this with a natural insecticide, Spinosad (sold as Ferti-lome Borer, Bagworm, Caterpillar and Leafminer Spray or Monterey LG6135 Garden Insect Spray. I make a second application of this combination about 10 days to 2 weeks later. Apples and pears need biweekly applications of insecticide to prevent codling moth larvae (worms) until August 1st.

Slug and Snail Control Slugs and Snails are active much earlier than normal. It is time to apply bait around your perennial flowers and especially around any new plants you plant. Slugs can devastate Hosta plants as they start new growth. Iron phosphate baits—available under many trade names including Sluggo and Escar-Go—have the advantage of being safe for use around children, domestic animals, birds, fish, and other wildlife.


Allen Wilson

Allen has been writing about gardening for over 30 years. He is a retired professor of Horticulture.

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