Pg. 48-50 Field Evaluation of Synthetic Sex Pheromones Attracting Litchi Moth (Cryptophlebia peltastica) Males

The litchi moth, Cryptophlebia peltastica (Meyrick) (Lepidoptera: Tortricidae) is a pest of litchi, Litchi chinensis Sonnerat in South Africa. Cryptophlebia peltastica lays her eggs on the skin of the fruit and newly hatched larvae eat through the skin and into fruit flesh and seed. The aim of the present study was to test field responses of C. peltastica males to different dosages of the synthetic female pheromone Z-8-dodecenyl acetate (Z8-12:Ac). Trials were carried out in litchi orchards at Friedenheim, Malelane and Nelspruit. The Intercept A trap with sticky Intercept A Liners were used throughout. In the first set of experiments, three different concentrations of Z8-12:Ac in a Last Call matrix at a loading rate of 0.16% and 6% permethrin were placed in the traps on the sticky liner. The concentrations were 1, 10, 30 droplets per trap. A rubber septa with lmg/lure of Z8-12:Ac was also placed on the sticky liner of traps. Catches with the Z8-12:Ac were tested against blank traps, which served as a control. In the second set of experiments, four different concentrations i.e. 10, 20, 25 en 30 drops, were tested against a blank trap. In the first set of experiments no significant differences were present between the number caught in the traps. In the second set of experiments the best results at Friedenheim were obtained with the higher concentrations, while at Nelspruit the best results were obtained with 20 droplets. From the results it seemed that the higher concentrations attracted more moths than the lower concentrations. Further work is required to optimize the concentration for attracting C. peltastica.

Summary:

• The study focused on the litchi moth, Cryptophlebia peltastica, a pest damaging litchi fruit in South Africa by larvae feeding inside the fruit after eggs are laid on the skin.
• The aim was to test male moth responses to various dosages of the synthetic female sex pheromone Z-8-dodecenyl acetate (Z8-12Ac) in litchi orchards at Friedenheim, Malelane, and Nelspruit.
• Intercept A traps with different concentrations of the pheromone (1, 10, 20, 25, 30 droplets) and a rubber septa dispenser were deployed and catches were compared to control blank traps.
• Higher concentrations generally attracted more male moths, with the best results at Friedenheim and Nelspruit using around 20-30 droplets, though variation existed between sites.
• No significant catches were recorded on the Malelane farm likely due to lower moth populations.
• The pheromone trapping offers potential for monitoring the pest population, as currently no effective monitoring method exists for C. peltastica.
• This research aims to improve targeted pest management by optimizing pheromone concentrations for more effective monitoring and control.