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It is true that we had a few cold days this winter and a few cold days in early spring. However, we got through the winter and spring quite easily. That's the good news. The bad news is that many insects also had an easy time of it. When I went through my Master Gardener training, I remember one of the professors saying the easier the winter, the more severe the Dutch Elm infestation will be.

A mild and early spring will bring on the iris borer sooner than normal. The borer is the most destructive pest of iris. The eggs of this borer normally hatch when iris has four to six inches of new growth. New growth may already be that high by the first week in April. However, that was too soon for iris borer eggs to hatch because they need temperatures consistently in the 50s.

If you think you have an iris borer problem, an insecticide application is necessary this spring. The timing is important because the damage is usually not noticed until it is too late for effective control. Two options are acephate (Orthene) or spinosad (Bulls-Eye). It is important to time the application when eggs are just hatching. This is approximately when new growth is about four to six inches high. A repeat treatment 10-14 days after the first application may be necessary. Dimethoate (often sold as Cygon 2E) was a commonly used product for iris borer management, however it was canceled in 2002 and is no longer available.

In early to mid-may canker worms may appear. These caterpillars feed on the leaves of many hardwood trees, especially elm, hackberry, and apple. If management is necessary, there are many insecticide options. Theses include acephate (orthene), malathion, carbarye (sevin), and Bacillus theuringiensis (BT). B.T. is a bacterial insecticide that is very low in toxicity toward people and animals. Management is most effective when caterpillars are 1/2 inch or less when treated.

Cabbage and onion maggots can attack broccoli, radishes, cabbage, turnips, and onions. Adult maggots start laying eggs in early to mid-May and can continue to the end of the month. You can help prevent egg-laying by using a floating row cover, placed in your garden when adult flies are laying eggs.

Adult asparagus beetles attack asparagus as it first starts growing. This feeding can cause the asparagus to bend over and deforms the plant into a condition called shepherds crook. If you find beetles on more than 10 percent of your plants you probably should use an insecticide. You can use Carbaryl (sevin), Eight, or malathion. Be sure the insecticides you use are labeled for asparagus.

Plum curculio adults are active on apples about the time the trees bloom. If it's necessary to protect your apples make an insecticide application at petal fall.

That is when most of the petals have fallen.

Make a second application 10 days after the first treatment. You can use phosmet (Imidan) or malathion and methoxychlor.

If Eastern tent caterpillars appear, it's usually happens in mid-May. These common caterpillars construct silken tents in Apple, Cherry, flowering crabapple, plum, and chokecherry trees as well as ash, birch, maple, willow, and other hardwood trees. Remove the webbing when the caterpillars are inside the tent. There are many registered insecticides if it is necessary to treat the foliage. Be sure most caterpillars are one inch or less.

Another mid-May pest is the honey locust plant bug. These bugs appear about the time the honey-locust leaf buds open. Early feeding on leaves can cause leaves to become dwarfed and cupped, resembling herbicide injury. If it is necessary to protect your honey locust from plant bugs, apply a registered insecticide, such as acephate (orthene) or permethrin. The time to spray is just after bud break or as soon as you see plant bugs to minimize injury to the plant.

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Tuesday, May 8, Jeff Gillman, an Associate Professor in the Department of Horticultural Science at the University of Minnesota, will be discussing pesticides and garden remedies. He is the author of the book The Truth About Garden Remedies. There are many recommendations targeted at the homeowner about what works and what doesn't for controlling pests. This talk will investigate appropriate (and inappropriate!) pesticides and remedies for garden insects and diseases.

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We still have some bare root plants for sale although we are running low on some varieties.

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Due to the office hours at the Extension Office in North Branch being reduced, some requests for information may be delayed. Therefore, I do not mind if you call me at my home regarding plant orders or class offerings. My number is 651-257-4496.

Class brochures as well as the plant order forms are available on the website at www.extension.umn.edu/county/chisago or you can call the Extension office at 651-674-4417 to have one mailed and to pre-register.

A cutback in staffing has made it necessary for the Extension Office to limit hours of operation. At present, the office will be open on Tuesdays and Thursdays. We would suggest that you call ahead to verify that the office is open before you stop by.

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