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Caterpillars of the European corn borer in the pepper, trichogramma wasps to fight them

Published on: | Created by: Roxanne S. Bernard


Anatis BioprotectionDespite the rain and the rather cool temperatures, the bell pepper and chilli pepper plants are starting to stretch their leaves in the fields of Quebec. In a few weeks, producers will have to protect their production against a well-known enemy: the European corn borer.

The European corn borer (Ostrinia nubilalis) is a pest moth that attacks several types of crops, including corn, beans, potatoes, tomatoes, apples , hop, bell peppers and chilli peppers. In these last ones, the moth lays its eggs on the foliage and the young larvae (caterpillars) once hatched penetrate the forming fruit. When eating, they cause damage that can lead to yield losses of up to 15%.

European corn borer larvae
Figure 1. Corn borer larvae - photo by Agricultural Research Service, the research agency of the United States Department of Agriculture- Public domain.

Controlling the European corn borer with insecticides, popular, but not without constraint

For the moment, chemical control is the most popular solution. However, the window for applying chemical insecticides is very short, as the migration of the young larva (caterpillar) occurs 24 hours after it hatches from the egg. Once in the fruit, it is then protected. Chemical control of the European corn borer requires 3 to 6 applications during the season.

But another very effective solution exists to control the European corn borer in the pepper, the trichogramma wasps, and they are easy to use :

Trichogramma wasps against the European corn borer

trichogramma wasps Trichogramma are tiny wasps that parasitize butterfly and moth eggs. In agriculture, they are mainly used to control corn borer (Ostrinia nubilalis), armyworms (Spodoptera sp.) and False looper (Trichoplusia sp.).

Trichogramma ostriniae pupae are glued to cards and introduced in the field. Once set up, adult trichogramma will emerge after 5 to 7 days, depending on environmental conditions. Upon emergence, the female trichogramma wasp will actively search for moth eggs on the surface of the pepper leaves. Once detected, she lays inside them. The trichogramma larvae will grow inside the moth egg and feed on the future caterpillar. This will cancel the future generation of Corn Borer.

Trichogramma against corn borer
Figure 2. A) Trichogramma ostriniae parasitizing European corn borer eggs B) adults ovipositing (scale = 1mm) C) parasitized European corn borer egg mass. ©Virginia Cooperative Extension

The efficacy of trichogramma wasps in peppers, studies prove it

Before introduction, it is advisable to do a screening to detect the presence of pests and the state of their populations.

In 2009 and 2010, l’institut de recherche et de développement en agroenvironnement (IRDA) with the collaboration of the University of Quebec in Montreal (UQAM) and Anatis Bioprotection, carried out a study aimed to determine the potential for using the trichogram Trichogramma ostriniae against corn borer in pepper cultivation. The team started to release at the rate of 250,000 trichogramma wasps/ha at the fruit set stage at 2 sites in Quebec. Introductions were made 10 days apart, for a total of 4 and 5 introductions during the season.

During the two years of experimentation, the results obtained demonstrated that:

  1. The trichograms parasitized 70.6% of the masses of moth eggs in 2009 and 66.7% in 2010.
  2. A reduction in damage by the moth of 41.5% in 2009 and 62.1% in 2010.
Graphique sur les trichogrammes

Trichogramma wasps against European corn borer in peppers - Grower results

In 2013 and 2014, project manager Marianne Lefebvre and agricultural technician Linda Roberge of the Prisme followed the introduction of trichogramma wasps in a bell peppers field at the company Serres et Jardins Girouard (Qc). In this study, the trichograms parasitized 33% of the egg masses in 2013 and 63% in 2014. During these two years, no insecticide treatment was done and the yield and quality of the fruits were great.

Trichogrammes sur une carte
Tricho-Pepper Trichogramma wasps pupae

Introduction of the trichogramma wasps in the pepper

For an effective treatment, it is important to respect the conditions of use of the trichograms.

Trichogrammes pour poivrons
Tricho-pepper card calculator

Length of the plot: m

Width of the plot: m

Tricho-peppers cards needed : / week

Tricho-gard cards distribution

Questions and answers on the introduction

When to start the introductions for the pepper?
Poivron stade de nouaison
It is very important to introduce the tricho-peppers cards before the initial phase of fruit formation.
How many cards do I need?
A card of Tricho-peppers covers 100 m2. For a 1 ha field, the producer will need 100 cards per week. Your sale representative can help you calculate the number of cards and the number of introductions required depending on your region and your culture history.
How long does the installation take?
For 1 hectare, the installation takes approximately 30 minutes.
How often are the cards changed?
Anatis Bioprotection advises to change the cards every 7 days. This allows to keep a constant pressure of Trichogramma wasps and not to forget to introduce them (which can happen, with introductions every 10 days).
How long do tricho-peppers cards keep?
Our tricho-peppers can be stored for up to 4 weeks in the refrigerator (4 to 10º C). We can send a batch of cards for monthly treatments
How many introductions will there be in total?
In general, between 4 and 5 introductions are necessary to control the European corn borer in the pepper*.
* Depending on the presence of univoltine / bivoltine breeds, the type of production (field, greenhouse and tunnel), the region and weather conditions.
Do I need skilled labor to make introductions?
No, setting up the Tricho-peppers cards is very simple and does not require professional training or application permits.

See the Tricho-peppers sheet

Additional information

  1.   - European corn borer - OMAFRA
  2.   - European Corn Borer in Sweet (Bell) Pepper

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