Reproductive status of overwintering potato psyllid: absence of photoperiod effects

Authors: Horton, David; Miliczky, Eugene; Munyaneza, Joseph - Joe; Swisher Grimm, Kylie; JENSEN, ANDREW - Washington State Potato Foundation

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/26/2014
Publication Date: 8/26/2014
Citation: Horton, D.R., Miliczky, E., Munyaneza, J.E., Swisher, K.D., Jensen, A. 2014. Reproductive status of overwintering potato psyllid: absence of photoperiod effects. Meeting Proceedings. 100-103.

Interpretive Summary: The role of daylength in preparing potato psyllid for arriving winter conditions has yet to be determined, and this lack of information has made it difficult to predict geographic range limits of this important pest of potatoes. Scientists with USDA-ARS, Yakima Agricultural Research Laboratory, Wapato, WA and the Potato Commissions of Washington, Idaho, and Oregon tested whether shortening days prevented potato psyllids from mating and developing eggs in preparation for overwintering. Results showed that short days had no effects on reproductive development of psyllids collected from Texas, California, or Washington. These results confirm observations in the literature for related species of psyllids which suggest that these insects are able to overwinter in any of several life history stages, and that this flexibility allows psyllids to adapt to any of a number of winter environments

Technical Abstract: We examined the effects of photoperiod on reproductive diapause of three haplotypes of potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae), collected from three geographic locations: south Texas (Central haplotype), California (Western haplotype), and Washington State (Northwestern haplotype). Psyllids were reared from egg hatch to adult eclosion under short- and long-day conditions, to determine whether short-days led to a lack of mating, delays in ovarian development, and accumulation of fat by female psyllids. Our expectation was that a reproductive response to short-days, if present, would be more likely to be exhibited by psyllids of the northern-latitude haplotype (Northwestern) than psyllids of the other two haplotypes. We also examined whether this species exhibited a photoperiod-controlled polymorphism in body size, as observed in other psyllid species, by comparing six body and wing measures of psyllids reared under short- and long-day conditions. Virtually 100% of females of each haplotype exhibited both egg maturation and mating at both long- and short-day conditions, providing no evidence that this species exhibits a photoperiod-induced reproductive diapause. Fat was present in most psyllids, although with higher probability of presence in short-day females than long-day females. Photoperiod had no effect on body size. We found differences among haplotypes in body size, with psyllids from Washington State (Northwestern haplotype) having larger wings and longer tibia than psyllids of the two southern populations. Our photoperiod results, combined with overwintering observations for this and other Triozidae, prompted us to hypothesize that potato psyllid – at least in the Pacific Northwest growing region – overwinters in a temperature-controlled quiescence rather than in a true diapause