Artificial diets for larvae of Anarsia lineatella Zeller (Lepidoptera: Gelechiidae).

Maintenance of an insect colony under laboratory conditions is prerequisite for its further study. However, numerous artificial diet formulas, such as dietary replacements or supplements, influence species growth and survivorship and display difficulties in utilization in laboratory settings. In this work, successful rearing in the laboratory is reported for the peach twig borer A. lineatella on artificial diet. The diet contains dry pindo beans (380 g), brewer's yeast (64 g) agar 31 g, 1360 ml distilled water and preservatives. It is a modification of an artificial rearing medium proposed for the development of the Tortricid Cydia pomonella. Larval survivorship, when developed on the above diet, is significantly higher (-90%) when compared to peach fruits (-60%) and to other diets that were initially tested (5-35%). Diet had no effect on larval developmental time when compared to fruits (27.1 +/- 0.4 and 27.2 +/- 0.5 days, respectively, at 25 degrees C and 65 +/- 5% RH). Light presence of 16:8h L:D did not appear to be a critical factor for a successful rearing of A. lineatella larvae in the laboratory. Type of diet had a significant effect on male (d.f. = 4,103, F = 18.562, P < 0.05) and female (d.f. = 4,91, F = 14.990, P < 0.05) pupal weights. Pupal weights, when they developed as larvae on the proposed 'pindo-bean' diet, ranged from 7.7 +/- 0.3-8.2 +/- 0.2 mg. First-instar larvae exhibited lower survivorship during development, regardless of rearing medium. Sex ratio, for individual larval rearing, was in all cases close to 1:1 regardless of tested rearing medium. More than five generations of A. lineatella were reared under constant conditions without observable adverse effects on development.

Temperature-dependent bionomics and modeling of Anarsia lineatella (Lepidoptera: Gelechiidae) in the laboratory.

Laboratory studies were conducted to assess the effect of constant temperatures (15, 20, 25, 30, and 35 degrees C) on life history traits of peach twig borer, Anarsia lineatella Zeller (Lepidoptera: Gelechiidae). Developmental rate, survival, longevity, and fecundity were studied in environmental chambers from individuals reared on peach, Prunus persica L., twigs until adulthood. Temperature-dependent relationships of various developmental events were characterized, and applied models were evaluated. Total developmental time ranged from 20.4 d (30 degrees C) to 124 d (15 degrees C). Lower developmental thresholds for egg-to-adult development assessed to 11.2 or 11.8 degrees C, according to a linear weighted regression or the reduced major axis method, whereas development required on average 400 degree days (DD) or 424.4, respectively. Survival was substantially reduced at lower (15 degrees C) and higher (35 degrees C) temperatures. First-instar larvae exhibited higher sensitivities during development in all treatments. Mean longevity ranged from 12.1 d (35 degrees C) to 45.8 d (15 degrees C) and from 10.4 d (15 degrees C) to 50.3 d (35 degrees C) for females and males, respectively. A significantly higher number of eggs was laid at the moderate temperatures (126.9 at 25 degrees C), whereas at the extremes, females laid the fewest (40.4 and 26.3 at 15 and 35 degrees C, respectively). A new model, based on a beta type distribution function, fitted on the temperature-dependant developmental data to predict population dynamics. Relative accuracy of the above-mentioned formula was validated using root mean square error (RMSE), index of agreement (d) and the mean square error quotient (E1,2) with respect to a proved model.

Flight patterns of Anarsia lineatella (Lep., Gelechiidae) in relation to degree--days heat accumulation in Northern Greece.

The flight patterns of the peach twig borer Anarsia lineatella (Zeller) (Lepidoptera: Gelechiidae) were studied in two important and representative regions of peach production in Northern Greece. In order to determine the seasonal occurrence of the species, adult male moth flight was monitored from April till October (2005-2006) using 8 pheromone traps. The observation areas were located at the regions of Veria (lat. 40.32 degrees North) and Velvendos (lat. 40.16 degrees North). The first flight was observed from early May to early June in Veria and from late May to mid June in Velvendos. The 2nd and 3rd flights were observed from late July to early August and from late August to late September in both regions. The degree-days required for the first generation (431 Veria, 371 Velvendos) were fewer than for the 2nd (661 Veria, 504 Velvendos) and the 3rd generation (675 Veria, 506 Velvendos). A lower threshold temperature of 100 C was used in calculating daily day-degrees from March 1st. All the above data are valuable for the development of prediction models and for decision making in order to achieve better timing of treatments. Considering the increasing interest of biorational insecticides where precise timing of treatments is extremely important, degree-day models could be a useful tool for improving their efficacy in IPM.