Submitted to: Southeastern Pecan Growers Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/11/2005
Publication Date: 7/15/2005
Citation: Cottrell, T.E., Hodges, G.S. 2005. Biology and management of scale insects attacking pecans. Southeastern Pecan Growers Meeting Proceedings. 98:52-55. Interpretive Summary: The predominant species of scale insect found attacking pecan across the southern US is the obscure scale. Populations of this scale on pecan can be economically damaging and should be controlled. The crawler stage is highly susceptible to control measures during the summer. During the winter, at least two applications of dormant oil (2%) applied to runoff is most often required to adequately manage this pest.
Technical Abstract: Species of scale insects are very diverse and attack a wide range of host plants. On pecan, various scale species can be found on limbs throughout the canopy and also on trunks. However, it is the obscure scale (Melanaspis obscura) that can cause problems when undetected populations increase. Chemical control of primary pecan pests can reduce natural enemy populations and lead to damaging levels of obscure scale in orchards. Well-timed control measures against the vulnerable crawler stage are effective against the univoltine pest. In addition, dormant oil sprays (2% oil) applied to runoff are necessary for management of scales with oil. It is important that the scale be entirely covered with the dormant oil as death is not by contact but rather by suffocation. Application volumes suitable for control of pecan weevil with contact insecticides are too low for control of scale insects with dormant oil.