Early-season phenology and temporal dynamics of the common asparagus beetle, Crioceris asparagi (Coleoptera: Chrysomelidae), in southern Minnesota

During the years 1991-1994, studies were conducted to determine the early-season phenology and temporal dynamics of Crioceris asparagi (L.) (Coleoptera: Chrysomelidae) in southern Minnesota asparagus. To document the early-season phenology, asparagus plots were sampled for egg, larval, and adult stages of C. asparagi during the months of May and June. Temporal dynamics of C. asparagi were determined by measuring the diurnal activity of adults and sampling asparagus plots at specific times (7 am, 9 am, 11 am, 1 pm, 3 pm and 5 pm) throughout May and June. We first detected C. asparagi adults in early May and they remained active throughout the sampling period. Eggs and larvae were also found; larval infestations on spears, however, were consistently lower than those for eggs. The temporal dynamics of C. asparagi adults showed that a higher percentage of asparagus plants were observed to be infested with beetles during the afternoon hours of 1 and 5 pm. The information provided in this paper illustrates the importance of determining the optimum time of day for sampling and will assist in properly targeting sampling efforts in future asparagus research and integrated pest management (IPM) programs.