Embrapa publishes guide for identifying natural enemies in vegetables

To assist producers in implementing integrated pest management (IPM) on their rural properties, with a focus on biological control, Embrapa researchers gathered in a publication, in the format of a field guide, a list with photos and descriptive information of the main natural enemies found in vegetable crops such as species of beetles, predatory flies and mites, bedbugs and parasitoid wasps.

The correct identification of natural enemies is the starting point for effective biological control, one of the pillars supporting IPM. “The purpose of the guide is to help farmers, technical assistance and rural extension professionals, consultants and students in the area of ​​Agricultural Sciences, in recognizing natural enemies commonly found in vegetable crops”, explains researcher Miguel Michereff Filho, from the area of Entomology at Embrapa Hortaliças (Brasília, DF).

Entitled “Guide for Identification of Natural Enemies in Vegetable Crops”, in addition to illustrative images of natural enemies, the document provides basic information about the life cycle, body characteristics and signs of action on pests that attack vegetable crops. Natural enemies are biological control agents and contribute to the natural mortality of pests in the field, that is, they are allies of farmers in combating agricultural pests and have a positive effect on the balance of the agroecosystem.

Vegetable crops are very susceptible to infestations by insect pests or mites and Estimates indicate that production losses could reach 80%, depending on factors such as climatic conditions, cultural practices and cultivar used. Therefore, knowing how to accurately identify which insects are beneficial is essential so that they are not confused with the pests themselves and end up being mistakenly eliminated with the use of pesticides.

The differences between predators and parasites

In the guide, natural enemies are divided into two groups: predators and parasitoids. Predators are natural enemies that feed on insects and mites that are harmful to vegetable crops. This group includes beetles, flies, bed bugs, earwigs, wasps, ants, praying mantises, mites and spiders.

“Many of the natural enemies categorized as predators are larger than their prey, with the exception of predatory ants and mites. They have the habit of walking on plants or the ground to find their prey and are usually generalists, that is, they consume what they can capture”, explains Michereff, adding that, in addition to adults, nymphs and larvae are also able to kill and consume the pests.

The natural enemies considered parasitoids are wasps, microwasps and flies which, when parasitizing other insects, cause the death of their host. They are smaller than their prey and act as specialists, that is, they choose a type of host and a specific stage of development. “Many of these natural enemies live a large part of their lives inside the host or attached externally to it. Most of the time, they go unnoticed by producers, who end up disregarding their importance as biological pest control agents in agricultural crops”, analyzes the researcher.

Control: chemical or biological?

The different types of pest control should not rival each other because IPM presupposes the association of two or more control methods, since when different practices are adopted, compatible with each other, several control fronts are created and, over time, efficiency increases as the phytosanitary problem reduces.

The simultaneous adoption of biological control and chemical control increases the chances of suppressing the target pest more quickly and contributes to production sustainability. For example, the release of natural enemies on crops, if carried out at the exact time and in the correct quantity, guarantees high levels of control and contributes to reducing the number of chemical product sprays.

Although the cost of biological control and chemical control is practically equivalent, there are indirect savings and other advantages associated with the adoption of IPM, such as, for example, a reduction of between 30% and 40% in the frequency of spraying on different vegetable crops. “There is also a demand from the consumer market for healthier foods, which may make producers rethink other means of control”, ponders the researcher.

Encouraging the adoption of MIP

The publication of the “Guide for Identification of Natural Enemies in Vegetable Crops” is part of the actions foreseen in the project “Promotion of Integrated Pest Management in Vegetable Production in the Federal District”, which aims to restore the adoption of good agricultural practices aimed at managing pests in four agricultural crops: strawberries, lettuce, tomatoes and peppers.

In addition to providing guidance documents, the project team is dedicated to providing training courses for technicians and rural producers. The objective of the training has been to diagnose and level knowledge so that, based on partnerships and institutional articulation, it is possible to install Technological Reference Units (URT) to implement MIP in these four important crops in the Federal District.

“We intend to contribute to the process of raising awareness in the production chain so that they incorporate IPM and understand the relevance of biological control in their work routine”, plans Michereff, saying that the main objective will be to contribute to the rationalization of the use of pesticides and to the production of foods of high nutritional quality and completely safe for human health.

The project is carried out in technical cooperation with Emater/DF and with funding from the Federal District Research Support Foundation (FAPDF).