Submitted to: Pecan Grower
Publication Type: Trade journal
Publication Acceptance Date: 7/16/2004
Publication Date: 7/25/2004
Citation: Cottrell, T.E. 2004. Importance of pecan weevil management during a light crop year. Pecan Grower. v. 15:16-19. Interpretive Summary: Although it is tempting to save insecticide costs by not managing weevils during an off-crop year, this management decision could be costly in the future as it allows weevil populations to build up in orchards. Even during light crop years, pecan weevils should be controlled. Weevils are adept at finding trees with nuts and attacking. Rains following a dry spell soften the soil and allow for more-synchronous weevil emergence thus allowing for a well-timed insecticide application.
Technical Abstract: The pecan weevil usually is the most-damaging of the late season pecan insect pests. Direct damage to the marketable portion of the crop can be quantified allowing for a reasonable estimate of the economic loss incurred. However, the pecan weevil can also have lingering effects upon pecan production in future seasons. This is accomplished via management decisions by the grower which can alleviate or exacerbate pest problems. A light crop that does not justify the cost of weevil management during the current year, may cost even more (e.g., more damage and/or more applications) when most of those weevils emerge to attack the crop two years later. Weevil emergence can begin in early to mid-July but most weevils will emerge in August and September and emergence can be greatly affected by soil moisture. Dry soils either prevent or slow the emergence of adult weevils. Rains following dry conditions serve to synchronize weevil emergence allowing for a well-timed and very effective insecticide application.