Pesticide effects on natural enemies

Stephanie Williamson of the International Institute of Biological Control (IIBC) reports on achievements of a recent practical training course held for the Asia region on the evaluation of pesticide effects on natural enemies and the implications for pesticide registration.

Collecting natural enemies for identification. Photo IIBC/Stephanie Williamson

Visitors to Malaysia’s Deptartment of Agriculture Training Centre may have been surprised earlier this year to find a group of pesticide registration officials crawling on their hands and knees in a leucaena sapling grove, sucking up insects with the aid of a piece of tubing (see photo). They were in fact making an inventory of the beneficial insects knocked down from the saplings by a few puffs of a pyrethroid aerosol.
    Pest resurgence has occurred on a range of crops in Asia including fruit, rice, cotton, vegetables, cocoa and oil palm, when indiscriminate spraying has wiped out natural enemies of pests like whitefly and scale insects. By including tests on natural enemy impact in the pesticide registration process, products less harmful to beneficial species can be encouraged.
    The training course and workshop was co-organised by CAB INTERNATIONAL’s IIBC and the International Organisation for Biological Control (IOBC), in collaboration with Malaysian and German plant protection research bodies. The goal of ths course was to train people in how to measure pesticide effects on natural enemies in laboratory and field situations, using protocols developed by IOBC’s Working Group on Pesticides and Beneficials.
    Sixteen participants attended from Laos, Japan, Indonesia, Vietnam, Thailand, the Philippines, China, Pakistan, Malaysia, Myanmar (Burma) and Korea, including registration officers, IPM researchers and agricultural extensionists. Funding was provided by Germany’s GTZ Pesticide Service Project and the Swiss Development Corporation. Participants learnt how to carry out simple toxicity tests on organisms such as ladybirds, beetles, predatory mites and parasitic wasps and how to collect these control agents in the field and rear them. Another theme assessed the risks to natural enemies from pesticides commonly used in Asia, and how these risks could be better managed, for example, through more informative labelling of products.
    Participants were introduced to two major sources of information on pesticides effects. IOBC’s working groups on Pesticides and Beneficial Organisms have compiled data from joint testing programmes carried out on 144 active ingredients since 1980. More than 30 species of test organisms were studied, including parasitic wasps and flies, predatory mites and spiders, lacewings, predatory beetles and bugs, and insect-pathogenic nematodes and fungi. The results give the pesticide name, formulation and concentration tested, and score the effects on each natural enemy exposed on a scale from 1 (harmless) to 4 (harmful).
    The Ecotoxicology Database for Risk Assessment (EDRAS) developed at Southampton University aims to integrate existing knowledge on insect natural enemies and pesticide properties in order to predict side effects of chemical control methods and possible risk posed to beneficials. Users can search under chemical group or individual compound, crop type, mode of application, natural enemy group or species, lifestage, sex and host, amongst others, and EDRAS will interpret the stored data to produce a toxicity rating for the information entered. The database also includes microbial and botanical products and is continually updated.
    The course culminated in a two day workshop to discuss how standardised testing could be adopted and adapted to the Asian context. Participants’ reports revealed that while some countries have fairly good registration procedures, others face severe problems in regulating pesticide use.

Laos
Mr Ho Savongdy, leader of IPM research in rice reported that until recently Lao farmers made only limited use of pesticides and these were mainly insecticides in integrated rice. The department responsible for registration and regulation actively discourages pesticides except for botanical insecticides, small quantities of which are produced locally. Almost all other pesticides used in Laos are imported, often as development aid packages, particularly from Japan.
    Recently pesticide use has been increasing in vegetable production and unapproved pesticides can be found in provincial markets, including compounds banned in other countries. Laos has long borders with Thailand, China and Vietnam which not only allow the direct import of pesticides but also the spread of high input pesticide application practices. Although the country does not yet have procedures for pesticide registration regulation to control pesticide imports have been adopted. IPM research has focused on rice but there is no developed national extension service to help farmers adopt IPM practices.

China
China’s domestic pesticide production has increased at a rate of 11% per annum since 1979. In 1993, 220,000 tons of technical material were produced, half of which were organophosphates. Although average pesticide use in major crops is still much less compared with other Asian countries (2.7kg of active ingredient per hectare compared with 10.4 kg per ha in Japan) chemical control is becoming the dominant crop protection practice.
    Mr Zhang Wen-jun, head of Pesticide Evaluation and Registration, explained the difficulties faced by the dozen or so staff attempting to regulate the 400,000 tons of pesticides produced each year in over 800 factories. The major agrochemical companies are establishing production units in China and are running aggressive marketing campaigns. The Chinese plant protection extension system is supposed to implement IPM but in fact most extensionists have to obtain at least 30% of their salary and most of their operational budget by ‘free marketing’ which usually means selling pesticides.

Workshop recommendations
Participants developed recommendations (see below) and one immediate action was to set up the Asian Network on Natural Enemies and Pesticides (ANNEP). Course protocols and workshop reports will be produced in the form of a training manual later this year.

1. National and regional working groups (including regulators, researchers and industry) should be set up in the next 12 months to co-ordinate development and use of appropriate natural enemy side effects test methods.
2. Standardised test procedures and decision-making schemes following the IOBC and other models, should be adapted for use in Asia and incorporated within registration procedures, for harmonisation.
3. Side effects data should be collected from the region to draw up a simple natural enemy hazard classification. This system would provide a basis for registration agencies to develop procedures (e.g. via pesticide labelling) to restrict the use of products which pose a hazard to key natural enemies.
4. Training inputs should be developed on natural enemy side effects and their adverse economic impact, aimed at farmers, extensionists, researchers, industry and regulators.
5. A communication network should be set up immediately to encourage contact between participants, resource people, sponsors, IOBC and IIBC and facilitate access to the side effects databases.

For further information about the training course (to be repeated in 1996) or the ANNEP network contact: IIBC, Silwood Park, Buckhurst Road, Ascot, Berks. SL5 7TA, UK. Fax +44 1344 875007. Stephanie Williamson now works for PAN UK, Email stephaniewilliamson@pan-uk.org.

[This article first appeared in Pesticides News No. 28, June 1995, page 5]