# Assessment of infection of Stomoxys calcitrans larvae by entomopathogenic nematodes Heterorhabditis amazonensis NEPT11

## TL;DR

This study tested how well a type of nematode can kill fly larvae and found it has potential for pest control.

## Contribution

The study evaluates the effectiveness of Heterorhabditis amazonensis NEPT11 against Stomoxys calcitrans larvae.

## Key findings

- 200 EPNs/larva caused 48% mortality, the highest among tested concentrations.
- All treatments showed higher mortality than the control group.
- The nematode shows potential for controlling stable fly larvae but needs further study.

## Abstract

This study aimed to evaluate the virulence of Heterorhabditis amazonenses NEPT11 against larvae of Stomoxys calcitrans. Groups of 10 third-instar fly larvae were deposited in Petri dishes, to which were added 50, 100 and 200 EPNs/larva in 4ml of distilled water. The volume of the control group was the same as the treated group, but without EPNs. Larval mortality was observed daily, until larvae died or adults emerged. The Petri dishes were kept on laboratory shelves at 27 ± 1 °C and 70 ± 10% RH. The experiment was replicated six times. A regression analysis revealed quadratic behavior with increasing concentrations, indicating that the concentration of 200 EPNs/larva (48%) was the most efficient among the tested concentrations, while concentrations of 50 and 100 EPNs/larva killed 26.6 and 40% of larvae, respectively. In general, none of the treatments resulted in a mortality rate of more than 50%, but all the treated groups exhibited a higher mortality than that of the control group. It is concluded that the EPN H. amazonensis NEPT11 shows a promising potential to control third-instar larvae of S. calcitrans. However, further studies are needed in different situations to better understand the activity of this organism against the immature stages of the stable fly.