Field trials were undertaken in Victoria and New South Wales, Australia, to discover whether synthetic sex pheromone, cis -8-dodecenyl acetate, could be used to control the oriental fruit moth, Cydia molesta (Busck), in peach orchards by the disruption technique. When pheromone was released at rates exceeding 5 mg/ha h from polyethylene capillary tubes males were generally unable to locate synthetic pheromone sources or live virgin females. By maintaining a constant rate of release per unit area it was possible to reduce the number of dispensers from one per 50 m 2 to one per 400 m 2 . There was no significant difference in disruption when pheromone was released from tree crowns at 3·5 m or lower down at 1·5 m. Shoot and fruit damage from trials in commercial orchards suggested that pheromone treatments were as effective as a full seasonal schedule of insecticide applications in reducing damage.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0007485300006143

Control of oriental fruit moth (Cydia molesta (Busck) (Lepidoptera, Tortricidae)) with synthetic female pheromone

Studies were designed to examine the effects of host plants (apple, Malus domestica Borkh., and peach, Prunus persica L.) on the development of oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae). Oriental fruit moth larvae developed faster on peach than on apple, both on fruit as well as on growing terminal shoots. On fruit, these differences were shown to cause significant changes in both the rate (approximately 20-60 degree-days earlier emergence on peach than on apple) and patterns of adult emergence among several cultivars of peaches and apples. Slopes of female emergence plots varied by host in 2003, with emergence occurring over a longer period on peach cultivars than on apple cultivars (with one exception). Slopes of male emergence curves did not differ by cultivar in 2003. These host-driven effects could impact the efficacy of traditional pest management approaches and probably complicate efforts to predictively model G. molesta populations in mixed cultivar orchards. Such developmental effects may help to explain previously observed differences in patterns of pheromone trap captures in peach versus apple orchards. Host-associated effects should be incorporated into future models to develop more realistic predictive tools and thus improve integrated pest management efforts.

Effects of orchard host plants (apple and peach) on development of oriental fruit moth (Lepidoptera: Tortricidae).

The phenology of oriental fruit moth, Grapholita molesta (Busck), on apple (Malus spp.) in North Carolina was studied using pheromone traps and egg sampling in abandoned and commercial orchards in 2000 and 2001, with subsequent development of an oviposition degree-day model and management studies in relation to codling moth, Cydia pomonella (L.), phenology. Oriental fruit moth eggs were found in greater numbers on leaves early and on fruit later in the growing season, on the top versus the bottom of the leaf surface, and on the calyx area versus the side or stem end of the fruit. A degree-day (DD) model to predict oriental fruit moth oviposition was developed based on temperature accumulations from peak moth trap capture of the first (overwintering) generation, by using 7.2 and 32.2°C as the temperature limits. The model predicted four ovipositing generations of oriental fruit moth with the second beginning 507 DD after peak moth catch. Using predictions of the oriental fruit moth and codling moth degree-day oviposition models, an experiment was conducted to determine the level of second generation oriental fruit moth control with methoxyfenozide applied under different scenarios for first generation codling moth. Methoxyfenozide was equally effective in managing codling moth and oriental fruit moth for all treatment timings.

Oriental fruit moth (Lepidoptera: Tortricidae) phenology and management with methoxyfenozide in North Carolina apples.

Studies were designed to examine the effects of host plants on oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), survival. G. molesta larval survival in the orchard was comparable between apple (Malus spp.) and peach (Prunus spp.) shoots, indicating that both host species can harbor large larval populations during the early season. G. molesta larvae used multiple shoots for feeding and development on peaches but usually only damaged single shoots in apple. Survival differences were present between peach and apple fruit, but this survival was affected by fruit maturity level. Generally, larval survival higher was in ripening peach fruit than in green, immature apple fruit. Larval survival varied among several apple cultivars, indicating that cultivar-level variability needs to be considered. These host-associated effects may impact efforts to predictively model G. molesta populations in commercial orchards where multiple host plant species, or different cultivars of the same species are often grown in proximity. Thus, host-associated dynamics should be included into future population models that underlie management programs.

https://bioone.org/journals/Journal-of-Economic-Entomology/volume-99/issue-4/0022-0493-99.4.1299/Comparative-Survival-Rates-of-Oriental-Fruit-Moth-Lepidoptera--Tortricidae/10.1603/0022-0493-99.4.1299.pdf

Comparative survival rates of oriental fruit moth (Lepidoptera: Tortricidae) larvae on shoots and fruit of apple and peach.

SUMMARY. 1. The reliability of the simple frequency, Janetschek, Cassie and Dyar's law methods for determining or corroborating instars of mayflies and stoneflies was evaluated using data from published studies, a population of Baetisca rogersi and populations simulated through use of random numbers and generated normal distributions.



2. The Janetschek and Cassie methods are variations of the simple frequency method that offer no significant advantage. Modes of the Cassie method, thought to represent instars, are much more difficult or impossible to detect than are the corresponding peaks of the other two methods.



3. Overlap in size between adjacent instars can lead to false instar peaks or modes in frequency plots. The potential for overlap in mayflies and stoneflies is greatly increased, compared to other insects, because of their large number of instars and known developmental variability. The normal distribution simulations demonstrated that instar size variability as low as 5–7.5% COV (coefficient of variability) may lead to false instar peaks when the number of instars is in the typical range. These simulations also indicated that even simple frequency plots with distinct peaks may result in inaccurate instar determinations.



4. The number of size classes used in an analysis was correlated with the number of peaks or modes revealed. The number of peaks greater than zero in the Janetschek plots for the Baetisca rogersi population varied from 5 to 53 as the number of size classes was varied from 20 to 188. Similarly for the random number simulations. the number of peaks varied from 6 to 41 as the number of size classes varied from 22 to 127.



5. Dyar's law semi-logarithmic plots do not corroborate instars determined through frequency methods, because the uniform spacing of‘instar’data points is the direct result of the uniform spacing of peaks in frequency plots of most data sources (including random numbers), whether or not peaks actually indicate instars. Also Dyar's law plots will‘corroborate’different numbers of instars depending on the peak selection criteria used. The potential for corroborating instars through supplemental rearing and best-fit analysis is discussed.



6. The future of mayfly—stonefly instar determination lies in the increased and more rigorous application of the rearing and Palmen body (mayflies only) methods.

Errors in instar determination of mayflies (Ephemeroptera) and stoneflies (Plecoptera) using the simple frequency, Janetschek, Cassie and Dyar's law methods

Laboratory tests, at constant temperatures, were conducted to evaluate quantitatively the influence of temperature on development of the Oriental fruit moth, Grapholitha molesta (Busck). The results showed that at the highest temperature (30°C) some larvae had four instars and some had five, indicating a mixed population. Fifth instar larvae developed only at the highest temperature (30°C) where larval development was also most rapid. It can, therefore, be assumed that the Oriental fruit moth has four distinct larval instars when reared in the laboratory at 15°–24 °C.

Effect of constant temperatures on the number of larval instars of the oriental fruit moth, grapholitha molesta (lepidoptera: tortricidae)

Studies of fecundity and behaviour of the oriental fruit moth, Grapholitha molesta (Lepidoptera: Tortricidae), on the Niagara Peninsula of Ontario

Development of methods for sampling the oriental fruit moth, Grapholitha molesta (Lepidoptera: Tortricidae), in an Ontario peach orchard.

Parasitism of the oriental fruit moth, Grapholitha molesta (Lepidoptera : Tortricidae), in an unsprayed peach orchard on the Niagara Peninsula, Ontario.

Jean R. Proctor

Papers

Effect of constant temperatures on the number of larval instars of the oriental fruit moth, grapholitha molesta (lepidoptera: tortricidae)

Studies of fecundity and behaviour of the oriental fruit moth, Grapholitha molesta (Lepidoptera: Tortricidae), on the Niagara Peninsula of Ontario

Development of methods for sampling the oriental fruit moth, Grapholitha molesta (Lepidoptera: Tortricidae), in an Ontario peach orchard.

Parasitism of the oriental fruit moth, Grapholitha molesta (Lepidoptera : Tortricidae), in an unsprayed peach orchard on the Niagara Peninsula, Ontario.