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Reproduction Weevils in Forestry

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February 1, 2019

Announcer: Farm and Family is a production of the Mississippi State University Extension Service.

Amy Myers: Today we're talking about reproduction weevils in forestry. Hello, I'm Amy Myers and welcome to Farm and Family. Today we're speaking with Dr. John Kushla, Mississippi State University Extension Forestry Specialist. John, why are we talking about reproduction weevils today?

Dr. John Kushla: Well, Amy, winter is the time of year for reforestation. Most seedlings are sold as bare root, which are best planted when they're dormant. Our reforestation planting season is late December through mid-March.

Amy Myers: Now what are reproduction weevils?

Dr. John Kushla: There are two species of weevils that attack pines, the pales weevil, hylobius pales, and the pitch-eating weevil, pachylobius picivorus. Both are in the family Curculionidae. The adults are active 10 to 12 months of the year, with the lowest activity during winter.

Amy Myers: Now which pine species are susceptible?

Dr. John Kushla: All the pines that grow in the Southern United States. This includes loblolly, long leaf, short leaf, slash, pond, sand, spruce, and Virginia pines. These weevils are attracted to freshly cut stumps and logging slash.

Amy Myers: If weevils are attracted to stumps, what makes that a problem?

Dr. John Kushla: Well, the adults will feed on the freshly cut pine stumps and roots. They'll lay their eggs in the soul or the leaf litter and several months later, new adult weevils will emerge looking for food. If that cut over site has been replanted, the emerging adults will feed on the newly planted seedlings. In situations like this, damage can be extension. 30% or 60% or more of the seedlings maybe eaten. Extensive damage will require replanting.

Amy Myers: What do these reproduction weevils look like?

Dr. John Kushla: On pine seedlings, the weevils will feed by chewing through the bark along the root collar, main stem and branches. Light damage will appear as small shallow patches. Resin often covers the wounds and crystallizes, giving the seedling a sugary appearance. Heavy feeding will strip the needles of bark and ... Excuse me. It will strip the seedlings of bark and needles leaving bare stems.

Amy Myers: Now what can be done to control reproductive weevils?

Dr. John Kushla: There are two courses of action. The first relies on the life cycle of the weevil and the date harvesting is finished. Generally, there are one to two generations per year. Weevils feed on the freshly cut stumps or newly planted pines. The landowner should delay replanting the site if harvesting finishes between June through December. Wait a year and the weevil population will die out before the area is planted the trees.

Amy Myers: Well, what if a landowner does not want to wait?

Dr. John Kushla: In that case, the second method of control should be used, which is an insecticide dip or spray. Many seedling nurseries will sell permethrin-treated seedlings for planting. At just a few dollars more per thousand, this is the cheapest route for a landowner, but planning ahead is necessary. Of course, tree planters will need to wear a protective equipment, namely rubber gloves, in planting these seedlings. If treated seedlings cannot be purchased, post plant spraying with labeled insecticides is then required and that will be more expensive to do.

Amy Myers: Okay. Give me a summary of what we've talked about today regarding reproduction weevils in forestry.

Dr. John Kushla: Reproduction weevils include the pales weevil and the pitch-eating weevil. They feed on fresh pine stumps. If harvesting is finished between June through December, landowners should postpone planting an additional year. Otherwise, they should purchase insecticide-treated seedlings to plant. If you have any further questions, contact me at 662-566-8013 or your local extension office.

Amy Myers: Thank you so much. Today we've been speaking with John Kushla, Mississippi State University Extension Forestry Specialist. I'm Amy Myers and this has been Farm and Family. Have a great day.

Announcer: Farm and family is a production of the Mississippi State University Extension Service.

Department: Forestry

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