Evaluation of augmentative biological control options against fruit and shoot borer, Conogethes punctiferalis (Guenée) (Lepidoptera: Crambidae) in guava in India

Background Conogethes punctiferalis (Guenee) (Lepidoptera: Crambidae) has emerged as one of the important pests of guava in Punjab, India. Chemical insecticides have been used for its management, which could have serious implications on environmental and human health. As an alternative to chemical insecticides, biocontrol is the most appropriate alternative for its eco-friendly management. Two field experiments were therefore, conducted to evaluate efficacy of two biocontrol agents, Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) (egg parasitoid) and Chelonus blackburni Cameroon (Hymenoptera: Braconidae) (egg-larval parasitoid) against the borer during rainy season, 2020 and winter season, 2020-21.Results Four releases of both parasitoids at various dosages were carried out at weekly intervals starting from first week of July in rainy season and first week of October in winter season. Trichogramma chilonis @ 2000 parasitized eggs per tree was the best in reducing the fruit damage and increasing yield and net income over check in both rainy as well as winter season crops. There was 73.6% reduction in damage over control, 1.70 Metric tons (MT) increase in yield over control and 258.36 US $ per acre increase in net income over control in rainy season crop. During winter season, there was 62.5% reduction in damage, 1.98 MT increase in yield and 488.23 US $ per acre increase in net income over control.Conclusion Four augmentative releases of T. chilonis @ 2000 parasitized eggs per tree successfully controlled the fruit and shoot borer incidence in guava during rainy and winter season.

Automated summary

Releasing 2000 parasitized eggs of Trichogramma chilonis per tree proved to be the most effective method in reducing fruit damage, increasing yield, and net income over the control group during both the rainy and winter seasons. In the rainy season, there was a 73.6% reduction in damage, a 1.70 metric ton increase in yield, and a $258.36 per acre increase in net income over the control group. During the winter season, there was a 62.5% reduction in damage, a 1.98 metric ton increase in yield, and a $488.23 per acre increase in net income over the control group.