# The greenhouse as an integrated management strategy for Prodiplosis longifila Gagné, 1986: effects on infestation and pesticide use

## TL;DR

Greenhouses reduce tomato infestation by Prodiplosis longifila and pesticide use, offering a sustainable solution for tomato farming in Ecuador and similar regions.

## Contribution

Demonstrates that greenhouse cultivation combined with biorational pesticides and anti-aphid mesh effectively manages Prodiplosis longifila infestations.

## Key findings

- Greenhouse infestation levels were significantly lower (13-21.9%) compared to open fields (61.3%).
- Biorational insecticides like spinetoram and abamectin showed over 80% efficacy in greenhouses.
- Anti-aphid mesh acts as a physical barrier to reduce infestation and pesticide use.

## Abstract

Tomato production on the Ecuadorian coast is primarily carried out in open fields and has declined due to infestation by Prodiplosis longifila. Its short life cycle and rapid recolonization necessitate intensive chemical control, generating selection pressure and environmental risks. P. longifila exhibits high ecological plasticity and, due to its potential for expansion, has been included by the European and Mediterranean Plant Protection Organization (EPPO) and the European Food Safety Authority (EFSA) on the list of priority pests, with a risk of establishment in temperate regions of Europe and coastal areas of the Mediterranean.

Given the urgent need for sustainable strategies to revitalize tomato production, the objective of this study was to evaluate the impact of greenhouse use by comparing infestation levels, population density, the effectiveness of sticky traps, and pesticide efficacy in two cultivation systems: open fields and greenhouses.

The population dynamics of Prodiplosis longifila varied significantly among the cultivation systems. In greenhouse, infestation above the threshold ranged from 13% to 21.9%, while in open field it reached critical levels of 61.3%. Monitoring adults using traps is not a good indicator of abundance. Pesticide efficacy varies depending on the environment and infestation level. In greenhouse, the biorational insecticides spinetoram and abamectin achieved efficacies exceeding 80% in infestations of 10% to 20%, Azadirachta indica caused burns at high temperatures, and the efficacy of abamectin decreased. In open field, the neonicotinoids acetamiprid and imidacloprid achieved efficacies of up to 90% in extreme infestations (50%–61%), and the efficacy of thiamethoxam + lambda-cyhalothrin decreased after the third application.

A positive correlation was observed between temperature and larval density, while relative humidity had a negative effect. The results demonstrate that direct monitoring is an effective tool for optimizing the number of applications and that anti-aphids mesh is a physical barrier to reduce infestation, allowing for the rational use of pesticides.

The use of anti-aphid mesh in greenhouse significantly reduces infestation by P. longifila, decreases the frequency of spraying, and promotes the selection of biorational pesticides. This positions greenhouses as an alternative for revitalizing tomato production in areas affected by this pest. The results are relevant for tropical contexts and provide valuable information for designing prevention and management policies in at-risk regions.