Availability and location of cocooning sites for diapausing codling moth larvae (Cydia pomonella (L.)) (Lepidoptera: Tortricidae) on mature and young apple trees

[No abstract available

Effect of temperature on the oviposition, longevity and mating of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae)

The effect of temperature on the oviposition, longevity and mating of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae) was investigated. The preoviposition development time ranged from 2.54 days at 21°C to 7.54 days at 15°C. The lower threshold temperature for the preoviposition period was 11.4°C with a thermal requirement of 22.8 degree-days. Moths did not mate and few eggs were laid at temperatures below 15°C or above 27°C. The mean adult longevity of summer moths, from pupae of larvae leaving fruit in December through to February, was 11.7 days when exposed to fluctuating temperatures (range 14.4-37.5°C) and 22.5 days at constant temperatures of 15,17,19 and 21 ± 1°C. At constant and fluctuating temperatures longevity decreased with increasing temperature; thus spring moths lived longer than summer moths. Significantly more eggs were laid by summer moths at constant, compared to fluctuating temperatures. At fluctuating temperatures the mean number of eggs per female was 92.6 for spring moths and 121.2 for summer moths.Articl

Development rates of the embryonic and immature stages of codling moth, cydia pomonella (L.) (lepidoptera: Tortricidae), at constant and fluctuating temperatures

Development rates of the egg, larval and pupal stages of codling moth, Cydia pomonella (Linnaeus), on apples were determined at constant temperatures of 15, 17, 20, 25 and 30 ± 1 °C and at fluctuating temperatures. There was a linear relationship between rate of development and temperature over the range of temperatures used. The lower threshold temperatures for embryonic, larval and pupal development were 11.1, 7.9 and 9.9 °C, respectively. The degree-days required to complete embryonic, larval and pupal development were 80.1, 345.5 and 280.0, respectively. The responses of the different stages of C. pomonella to constant temperatures were similar to those under fluctuating temperatures. It is suggested that a base temperature of 10 °C be used in South Africa for calculating degree-days in predicting phenological events such as first egg hatch.Articl

Validation of the phenology model for the codling moth, Cydia pomonella (Lepidoptera: Tortricidae), in South African pome fruit orchards

The codling moth, Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae), is a key pest of pome fruits in theWestern Cape, SouthAfrica. Up to 1993, the industry recommendation for commencement of the codling moth spray programme was at 75%petal fall in order to avoid the negative impact of organophosphate sprays on bees during bloom. However, codling moth can emerge, mate and oviposit before and during full bloom in pome fruit orchards. Consequently, petal-fall does not necessarily correspond with the commencement of egg-laying or first egg hatch. The availability of insecticides with a softer environmental profile made it possible to apply sprays earlier than 75 % petal-fall. The development of phenology models provided a means of accurately predicting biological events such as the initiation of egg-laying and first egg hatch. Using lower and upper development thresholds of 10 °C and 32 °C, respectively, and hourly temperature recordings, phenology models were evaluated by comparing the number of degree-days (°D) accumulated using a selection of three biofixes, and date of first egg hatch. The number of °D accumulated from the selection of biofixes to first observed egg hatch varied from 130.7 to 179. The least variation in the number of °D between biofix and first egg hatch occurred when the second trap catch was used as the biofix. A biofix based on the first evening when the temperature reached or exceeded 17 °C at 18:00 after first trap catch also showed less variation than when the biofix was based on first trap catch. The mean number of °D at which 50%of the moths of the first flight emerged was 166.6 °D, while the mean number of °D at which 50 % oviposition occurred was 290 °D following biofix. The number of °D between the second and third flight biofixes varied between 488.7 and 531.2 °D, with a mean of 508.1 °D. The results are of significance in improving the timing and reducing the number of insecticide sprays for codling moth control

Head capsule widths and the rate of development of the instars of codling moth, Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae)

Head capsule widths of the instars of codling moth, Cydia pomonella (Linnaeus), a severe cosmopolitan pest of apples, were measured for laboratory-reared larvae and two cohorts of field-reared larvae. At the same time the accumulated degree days to reach the various instars was estimated. The results show that there were always five distinct instars. By measuring the head capsule width of larvae found inside infested apples and using the degree day data, pest managers can determine the instar, larvae age, and therefore when the fruit was entered. This information may give important clues towards understanding the reasons for control failure.Articl

Field observations on oviposition of codling moth, Cydia pomonella (Linnaeus) (Lepidoptera: Olethreutidae), in an unsprayed apple orchard in South Africa

Oviposition of the codling moth, Cydia pomonella (Linnaeus), was studied from 1985 to 1989 in unsprayed apple orchards on the Elgin Experiment Farm, Grabouw, Western Cape Province. There was a significant difference in the site of oviposition, more eggs being recorded from the bottom half of the western and southern aspects of the tree. There was also contingency between the time o f year and level (upper half, lower half) in the tree. Moths of the first generation preferred the bottom half of the tree and second and third generation moths the top half of the tree. The preferred oviposition sites on Granny Smith (GS) and Golden Delicious (GD) cultivars, in order of preference, were leaves, fruit and wood. More eggs were laid on the fruit of GS spurs (35.6 %) than on those of GD spurs (10.7 %). On fruit spurs, there was a significant increase in the number of eggs on GD leaves, and GS fruit over the season, whereas the number of eggs on GS leaves and GD fruit remained constant. On branches, there was an increase in the number of eggs on GD and GS leaves, but not on the fruit or wood. The distribution within different fruit-bearing classes (1-4 fruit per spur) was random only for one fruit per spur, while on the other spur classes clustering occurred.Articl