BIORATIONAL CONTROL METHODS FOR INSECT PESTS OF POTATO
Location: Fruit and Vegetable Insect Research
Title: Insecticidal Activity of Entomopathogenic Fungi (Hypocreales) for Potato Psyllid, Bactericera cockerelli (Hemiptera: Triozidae): Development of Bioassay Techniques, Effect of Fungal Species and Stage of the Psyllid
Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 7, 2009
Publication Date: October 28, 2009
Citation: Lacey, L.A., De La Rosa, F., Horton, D.R. 2009. Insecticidal Activity of Entomopathogenic Fungi (Hypocreales) for Potato Psyllid, Bactericera cockerelli (Hemiptera: Triozidae): Development of Bioassay Techniques, Effect of Fungal Species and Stage of the Psyllid. Biocontrol Science and Technology. 19:957-970. DOI: 10.1080/09583150903243904 http://www.informaworld.com
Interpretive Summary: The potato psyllid is a serious pest of potato and related vegetables. It has recently been implicated in the causing of a disease of potato known as Zebra chip, This disease is responsible for millions of dollars in losses to the potato industry in the southwestern United States, Mexico, Central America, and New Zealand. The conventional means of control of potato psyllid is with broad spectrum chemical pesticides. In an effort to develop alternative methods of control that are safe for the environment and the food supply, ARS scientists at the USDA-ARS laboratory in Wapato, WA initiated research on insecticidal fungi for control of potato psyllid. They studied three fungi with known insecticidal activity for other pest insects. They observed good insecticidal activity of the fungi on adult and immature psyllids. With additional research on the effects of potato psyllid under field conditions, these fungi may permit control of potato psyllid without the application of undesirable chemicals.
The potato psyllid, Bactericera cockerelli (Šulc), is a pest of potato, tomato, and some other solanaceous vegetables and has also been incriminated in the transmission of a bacterial pathogen, Candidatus Liberibacter solanacearum, resulting in a serious disease known as “zebra chip”. Although there are several reports of fungal pathogens in psyllids, there are none from B. cockerelli, nor have any fungi been evaluated against it. Five isolates of fungi, one Beauveria bassiana, two Metarhizium anisopliae and two Isaria fumosorosea, were bioassayed against B. cockerelli on potato leaves under ideal conditions for the fungi. All applications were made using a Potter spray tower. With the exception of dosage-mortality studies, all other applications were made using 107conidia. All isolates except B. bassiana, produced 95-99% mortality in adults 2-3 days after application of conidia and 91-99% in nymphs 4 days after application. The commercially produced Pfr 97 isolate of I. fumosorosea and F 52 isolate of M. anisopliae were used for evaluating of the effect of nymphal age and concentration of conidia on mortality. Pfr 97 applied at 107 conidia per ml produced 95% corrected mortality in both 1st and late 3rd instar nymphs. The F 52 isolate produced 96% corrected mortality in 1st and 3rd instar nymphs. Pfr 97 and F 52 were evaluated for insecticidal activity against 3rd instar B. cockerelli using 105, 106, and 107 conidia per ml. Mortality produced by I. fumosorosea Pfr 97 ranged from 83 to 97% and that of M. anisopliae F 52 was 88 to 95% at these concentrations.