Development times and fecundity of three important arthropod pests of strawberry in the United Kingdom

Abstract

The development rates and fecundity of three important pests of strawberry in the UK were determined over a range of temperatures. Development time of the strawberry tarsonemid mite, Phytonemus pallidus, from egg lay to adult, ranged from a mean of 28.4 days at 12.5ºC to 8.8 days at 25ºC. No nymphs developed to adult at 10ºC. Females lived for up to 45 days and laid a mean of 24.3 and 28.5 eggs at 20ºC and 25ºC respectively. Total development time from egg lay to adult for the strawberry blossom weevil, Anthonomus rubi, ranged from a mean of 95.7 days at 10ºC to 18.2 days at 25ºC. Mean fecundity at 20ºC was 157.6 eggs, and the oviposition period averaged 71.6 days. When nymphs were reared on strawberry, development of the European tarnished plant bug, Lygus rugulipennis, from egg lay to adult, ranged from 83.8 days at 15ºC to 28.8 days at 25ºC. Development times on groundsel were shorter and ranged from 65.6 to 22.2 days at 15ºC and 25ºC. Only two nymphs developed to adults at 10ºC; no eggs hatched at that temperature. Mean fecundity at 20ºC was 75.4 eggs, but ranged from 23 to 179. Under a fluctuating temperature regime of 10ºC for 12 h:20ºC for 12 h, nymphs of L. rugulipennis took 40.3 days to become adult on strawberry, and 33.4 days on groundsel. Simple linear models fitted the developmental rate -constant temperature relationship well for all species, accounting for 95-98% of the total variation in observed developmental rates. Development under fluctuating temperatures illustrated the potential problem of extrapolating linear models beyond the conditions of the experiment.

Life tables and development of Amblyseius swirskii (Acari: Phytoseiidae) at different temperatures

“…It should be pointed out that our studies were conducted at constant temperatures. Studies conducted under fluctuating temperatures can produce somewhat different results (Hagstrum and Milliken 1991;Easterbrook et al 2003). We started our development time studies with eggs produced at 25°C and the average age of these was 8 h when they were placed in experimental conditions.…”

Strawberry blossom weevil Anthonomus rubi Herbst (Col.: Curculionidae): relationships between bud damage, weevil density, insecticide use, and yield

“…In spring the female deposits a solitary egg inside a flower bud which is cut off after oviposition, and the larvae and pupae develop inside the withering flower bud. A. rubi fecundity averages 15.4 eggs per week at 20°C in the laboratory (calculated from Easterbrook et al 2003). The species may also cut buds without a preceding oviposition ).…”

“…The species may also cut buds without a preceding oviposition ). The total development from egg to adult takes about 5 weeks, depending on temperature (Easterbrook et al 2003).…”

Evaluation of methods to control Phytonemus pallidus and Anthonomus rubi in organic strawberry production

“…The data on yield, fruit size, infected green fruits and counts of damaged buds were analysed by anova (GLM) for splitplot designs using MINITABÒ Release 14.1 (Ó 1972-2003. Differences between means were tested using Tukey's test.…”

“…The data were also analysed with repeated-measures anova with time as the repeated factor. All analyses of data for P. pallidus considered the split-plot design and were performed using SASÒ Release 9.1 (SAS Institute Inc., Cary, NC USA, 2002-2003. Comparisons were made using contrasts.…”