Question
QUESTION: I have been told that my evergreen trees (blue spruce and frazier firs) have bag worms and need to be sprayed twice to the tune of $900 for each application.  In addition to the bag worms the tips of one of my blue spruce is turning pink.  Yikes!  I would like to spray them myself but don't want to use any chemicals that are too toxic for my yard which is one acre.  We have about 35 trees that are approx 20 ft.  I have 2 dogs and 4 grandchildren.  Can you suggest something "safe" that we can apply?  I have had a bad year with bugs, having carpenter ants and borers treated professionally and pricey.  I am a nurse and have had contact with chemo drugs and am trained in handling chemical spills etc.

ANSWER: Chemical Control-Insecticide Sprays Stomach insecticides are very useful for control of bagworms. Remember that the plant foliage is to be thoroughly covered because the larvae are protected from contact by being in the silk bag. Again, early sprays against young larvae are more effective than later applications. Products registered for bagworm control are: acephate (Orthene),  bifenthrin (Talstar), carbaryl (Sevin), chlorpyrifos (Dursban), diazinon, dimethoate (Cygon),  malathion, nicotine sulfate, pyrethrum, and rotenone.

If you control them early in their life cycle they are fairly easy to control. If the tree is small hand picking them is best and easy.
To control the bagworms the easiest method is to hand pick or clip off the bags from the plants during the winter or early spring before the eggs hatch. I pick the bagworms off whenever I see them on a plant, no matter what the time of year. The bags should be destroyed by crushing or putting them in soapy water. When infestation is too heavy for hand picking a biological control such as BT spray can be used. BT (Bacillus thuringiensis) is a type of bacteria that only kills certain insects and does not affect humans or animals. It works well only on young bagworms and must be applied between June 15th and July 15th to be effective.

Insecticide sprays are effective against the young larvae but bags that are 3/4 inch long or longer are very difficult to control. The bacterium Bacillus thuringiensis is effective on young caterpillars, but the material must be ingested--so thorough plant coverage is essential. Spinosad very effectively works by contact and ingestion. Cyfluthrin and trichlorfon are recommended for larger larvae but again thorough coverage is essential.

Handpicking of the bags is the only control from fall through midspring so find a really bored child.  

Bt would be the safest insecticide but all are safe after they have dried. The concetration is low so even if the spray was gotten into before it dried it would not harm any animal or child.

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QUESTION: What is turning the tips of my blue spruce pink?  Someone told me its due to a red spider.  Will the same treatment that you suggested for bag worms also kill this pest?

Answer
The Bt will not kill the red spiders. The Spider mites are usually not killed by regular insecticides, so be sure to check the pesticide label to see if "miticide" is present. Pesticides claiming "for mite suppression" are usually weak miticides and will not perform well. There are few products available to the homeowner. Dicofol (=Kelthane) is registered for over-the-counter use but is difficult to find. Acephate (=Orthene), dimethoate (=Cygon), chlorpyrifos (=Dursban), diazinon, disulfoton (=Di-syston), and malathion have over-the-counter product labels but are considered weak miticides.