UACES Facebook Bagworms


July 2010

Question I have an evergreen tree in my backyard that is covered with the cocoons in the attached pictures. These insects seem to be destroying my tree. Can you tell what this is and what, if anything, I can do to get rid of the insects and save the tree? I've also noticed that they are spreading to the other evergreen in my yard. Thanks for your help.

AnswerWow, that is the most impressive damage I have seen from bagworms. These tiny insects started feeding in May. As the larvae crawls and feeds, they construct the sack or bag around their body which protects them from predators and insecticides. They are typically in their crawling/feeding stage for about a month from mid May through June depending on the weather. By now, the damage has been done--and your tree has had a lot of damage! Hand picking and destroying the bags can cut down on problems next year for neighboring trees, but this tree will take years to recover. If it were mine, I would cut it down and burn or destroy it now. If you have bagworms every year, you may want to implement a spray program on the needle type evergreens in mid May. One application a week with BT (Bacillus thuringiensis) or similar insecticide will work. Three applications a year should suffice. Bagworms prefer junipers, Eastern red cedars, Leyland cypress and arborvitae plants.

May 2010

Question I have two tall cedar trees that have been infested with bagworms every year. I have been able to pick most of them off...but I cannot reach the ones up high. I know that is the best way to get rid of them. I have read that Talstar One if applied in May can also be effective. Talstar contains Bifenthrin. Do you have an opinion about this treatment? Thank you.

AnswerThere are numerous insecticides to choose from including bifenthrin (trade name Talstar). You can also use the organic Bacillus thuringiensis (BT, Dipel, Thuricide) or carbaryl (Sevin) or Orthene. The key is to apply the insecticides according to label directions now through mid June when the bagworms are in their juvenile stage and before the individual bag or sac is constructed which protects them from insecticides and predators. Bagworms are usually active from mid May through mid June in central Arkansas. Once you see dried bags in late June on, the only control is hand-picking.

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