• Integrated Control of Subterranean Pests in South America

• Strategies for the Integrated Management of the Subterranean Burrower Bug Cyrtomenus bergi Froeschner (Hemiptera: Cydnidae) in the Cassava Crop

• Establishing a Program for the Integrated Management of the Cassava Crop’s Major Pests in the Colombian Departments of Valle del Cauca and Cauca

Integrated Control of Subterranean Pests in South America

Subterranean pests—Their study now forms a new component in CIAT’s Integrated Pest-and-Disease Management (IPDM) Project.

Why study these Pests?

White grubs and the burrower bug (Cyrtomenus bergi Froeschner), which feed on the roots of tropical crops, have become major pests during the last 20 years. Reasons for their having become so include diminished agrobiodiversity that favored their development, soil degradation, and excessive application of synthetic pesticides that depleted the ranks of their natural enemies.

What We Want to Do

Our immediate aims are to reduce crop losses caused by subterranean pests, and discover appropriate integrated pest management (IPM) strategies for their effective control.

By achieving these aims, we hope to also achieve other, more indirect, objectives. These are to reduce environmental degradation caused by excessive use of pesticides, and to transfer knowledge and technology for pest and disease management to farmers, extension workers, and other interested parties.

Organizing the IPM Project for Subterranean Pests

Hampering the control of these pests is our lack of knowledge about them and how to manage them. Compounding the problem is the great diversity of white grub species. We have therefore divided the component into two phases, the aims of which are as follows:

Phase I:  Diagnostic and strategic research

• Set up a network of scientists involved in soil arthropod research, and include the electronic compilation of relevant data, a communication network, and website.

• Diagnose problems from the farmers’ perspective and identify local existing knowledge and farming practices.

• Describe pest problems, for example, taxonomically identify white grub species, discover methods for rapidly identifying larvae, determine distribution and occurrence of species, and estimate yield losses and damage.

• Characterize the biology and behavior of soilborne pests, including the life cycles and population dynamics of principal species.

• Characterize potential biological control agents, that is, search for natural enemies, identify and propagate them, and make laboratory evaluations of their effectiveness for biological control.

Phase II:  Applied research and implementation

• Deploy natural enemies as biological control agents, that is, evaluate and validate promising control agents (e.g., nematodes, fungi, bacteria, predators, and parasites) in the field.
• With the participation of farmers, evaluate and adapt those farming practices that best control the pests, such as intercropping with repellent or attractant plant species.
• Through training, strengthen and enhance the capacity of national agricultural research systems (NARS), nongovernmental organizations (NGOs), extension workers, and farmers to handle these pests.

Expecting Positive Results from the Project

First and foremost, we expect small to medium-scale farmers of major tropical crops such as cassava, maize, peanuts, beans, potatoes, and onions in Latin America to benefit from increased crop yields. By adopting a farmer participatory research approach, we hope to greatly enhance the probability of farmers adopting newly developed integrated control technologies. Such a research approach will let us examine and understand local farming and knowledge systems, and the larger context within which they exist, thus develop appropriate technologies that meet the needs and priorities of farmers and other interested parties.

We also expect to enhance CIAT’s strategic research expertise, and the NARS’ capacity for research and technology transfer. Close links between the extension services of CIAT, NARS, and NGOs will ensure an excellent platform from which to successfully implement integrated management strategies (i.e., strategies of biological control, farming practices, and other control methods) for subterranean pests.

Because of the white grubs’ worldwide distribution, this research component will not only allow the development of integrated control strategies for subterranean pests in South and Central America, but also in other tropical regions.

Finally, this component gives Colombian students the chance to participate in research activities and to have the opportunity for receiving undergraduate and graduate training in the biological control of pests.

An Administrative Strategy for the Project

The IPDM Project will execute this research component, with intellectual support from the Hillsides Project, the Entomology Units of the Bean, Cassava, and Forages Projects, and the Participatory Research in Agriculture (IPRA) Project. Under CIAT’s coordination, GOs and NGOs will also conduct research adapted to specific local conditions.

Research activities will consist of laboratory experiments, surveys, and controlled field trials at CIAT’s experiment station.

In Phase I, the pest complex will be identified and key pest species described. Yield losses and crop damage will be defined.   Methodologies will be developed to identify the complex of entomopathogens and evaluate the efficacy of promising species to control the pests. Studies on farming practices that reduce pest attack will be initiated, including participatory diagnosis to identify the problem and its magnitude from farmers’ perspectives.  Existing local knowledge and farming practices used to control and manage pest attack will also be identified.

Phase II, in contrast, will be characterized by the application of farmer participatory research (FPR) approaches and structures (such as Farmer Field Schools, Local Agricultural Research Committees, and other interest groups) to test, evaluate, and adapt selected integrated control techniques with farmers. The capacity of NARS, NGOs, extension workers, and farmers will be strengthened through training.

Our Partners

CIAT

The Center has multidisciplinary research teams in agronomy, physiology, entomology, germplasm development, and economics. In particular, because of its experiences in on-farm and farmers’ participatory methodology and its established collaboration with NARS, the Hillside Project will help facilitate farmers’ integration into the research. CIAT also has facilities, including entomological research laboratories, greenhouses, and fields, that will help guarantee rapid initiation of experiments. The identification of promising natural enemies will be aided by the Center’s taxonomists, its considerable experience in biological control, collections of entomopathogens such as fungi and nematodes, and biotechnological techniques.

The Institute of Plant Diseases and Plant Protection (IPP) of the University of Hannover, Germany

The Institute has a strong background in biological control in both temperate and tropical environments. Within the framework of its English-language MSc horticultural program at the IPP, the University of Hannover will train two Colombian students in modern techniques of biological plant protection. They will actively participate in the IPDM component, developing suitable bioassay techniques for screening entomopathogens for white grub control.

The Department for Biotechnology and Biological Control (DBT) of the University of Kiel, and the E-Nema Company in Kiel, Germany

The DBT specializes in research on entomopathogenic nematodes of the genera Steinernema and Heterorhabditis for use in the biological control of insect pests. The DBT will participate in our project by identifying entomopathogenic nematodes and training CIAT research assistants in the mass production of these organisms.

The Federal Biological Research Centre for Agriculture and Forestry (BBA)

The BBA, in Darmstadt, Germany, has a long history of expertise in the use of entomopathogenic fungi against soil pests. The BBA will identify pathogens and give intellectual and logistic support for the development of biological control technologies.

The Colombian Corporation forAgricultural Research (CORPOICA) and the following universities: Universidad de Valle (Univalle) in Cali, the Universidad de Caldas in Manizales, and the Universidad Nacional in Bogotá.

CORPOICA coordinates national NARS that are already working on biological control agents of white grubs. Additionally, CORPOICA will facilitate the involvement of extension specialists in our project. CORPOICA’s station in Medellín and the University of Antioquia have laboratory and field expertise in the application of bacteria, entomopathogenic fungi (EPF), and nematodes (EPN) against white grubs . The Corporation will also contribute with strains of EPNs and EPFs, collected at various sites in Colombia, and will assist in identifying and testing pathogens. Corpoica's Rionegro Reasearch Center in Rionegro (Antioquia) will execute the project in potato fields in northeastern Antioquia, in coordination with CIAT. The Universidad de Caldas has expertise in the taxonomy of Scarabaeidae and will identify soil pests and their natural enemies in several agroecological zones of the department of Risaralda; the Universidad Nacional, with expertise in the study of entomopathogenic organisms, particularly nematodes, will do the same in the department of Cundinamarca. Students of Univalle are participating in the evaluation of the pathogenicity of several native entomopathogenic nematodes against the white grub Phyllophaga menetriesi.

Contact: Andreas Gaigl

Strategies for the Integrated Management of the Subterranean Burrower Bug Cyrtomenus bergi Froeschner (Hemiptera: Cydnidae) in the Cassava Crop

The Project’s Background

In the early 1980s, a new pest appeared in cassava (Manihot esculenta Crantz) crops. Known as the subterranean burrower bug (Cyrtomenus bergi Froeschner), it has spread through different areas and in various crops of economic importance, such as onion, peanut, asparagus, sorghum, sugarcane, maize, and various grasses. The pest has been detected in Colombia, other South American countries, and Central America. Losses in crop yield and product quality of more than 60% result not only from insect damage, but also from the indiscriminate use of insecticides, all to the environmental, social, and economic detriment of many farmers.

This pest’s appearance in Colombia and Panama may have resulted from cropping intensification during the 1980s, reduced numbers of local host plants, and the creation of simpler ecosystems. These changes may have led to the many factors behind host-plant resistance becoming neutralized by the pest’s rapid evolution.

Collaborative research between countries with common problems is a mechanism for disseminating and validating research already carried out, as for results obtained by CIAT on evaluating and identifying cassava varieties resistant to the pest. Likewise, such collaboration enables, at a reasonable social and economic cost, the expansion of knowledge on natural enemies associated with insect pests in major agricultural areas. These strategies can be incorporated into programs for integrated management to reduce pest populations and rationalize pesticide use. Following these considerations, CIAT and the Panamanian Institute of Agricultural and Livestock Research (IDIAP, its Spanish acronym) signed an agreement to evaluate possible alternatives for controlling the burrower bug.

Objectives

• To establish and evaluate in field trials, techniques for measuring the effect of entomopathogens (fungi and nematodes) have on controlling the burrower bug
• To visit the project’s areas of influence in which the cassava crop has been affected by the burrower bug, and implement activities aimed at controlling this pest
• To strengthen relationships between the Panamanian Foundation for Agricultural, Livestock, and Forestry Research (FIAFOR); IDIAP; the Ministry of Agricultural and Livestock Development (MIDA); CIAT; and the Latin American and Caribbean Consortium to Support Cassava Research and Development (CLAYUCA)
• To reinitiate contacts and discussions aimed at facilitating the Panamanian cassava-growing sector’s entry to CLAYUCA

Initial Activities

• Make reconnaissance visits to the agricultural areas of Valle de Antón, Ocú, Chiriquí, and Cerro Punta in Panama
• Contact farmers and technicians from IDIAP, MIDA, and other entities in Valle de Antón, Ocú, Chiriquí, Cerro Punta, and Panama City
• Establish experiments in the Ocú Plains (e.g., sampling, working in experiment plots, and defining protocols for monitoring experiments)
• Meet farmers in Ocú (38 persons) and Siogui Abajo (District of David in the Province of Chiriquí; 56 persons)
• Visit IDIAP’s nematology laboratory in Cerro Punta
• Meet technicians from MIDA’s Plant Sanitation Service, Panama City (14 participants)
• Take soil samples to search for entomopathogenic nematodes and fungi
• Establish and evaluate experiments on biological control agents

Other Activities

As the project develops, other activities will be carried out to better understand this pest’s behavior and discover <<add?>> other forms of control, that is:

• Through evaluations of 12 cassava germplasm materials, identify and select those that either tolerate or resist C. bergi
• Study population dynamics and estimate the damage caused by this pest on farms, for better understanding and later management
• Evaluate plant species with traits that reduce or repel the insect through exudates, repellent substances, or insecticides, using crop associations and studying their effect on the bug’s behavior and level of damage

Collaborating Institutions

• CIAT, Cali, Colombia
• IDIAP, Panama

Participants

• Anthony C. Bellotti, CIAT
• Bernardo Ospina, CLAYUCA/CIAT
• Elsa Liliana Melo, CIAT
• José Antonio Aguilar, IDIAP
• José Alberto Yau, IDIAP

Contact: Elsa Liliana Melo

Establishing a Program for the Integrated Management of the Cassava Crop’s Major Pests in the Colombian Departments of Valle del Cauca and Cauca

In Colombia, cassava has traditionally been planted in small areas of 1 to 3 hectares. Currently, however, these plantings are increasing to more than 10 ha. This change from small to large plantings has been accompanied by ever-growing plant health problems. Confronted with this situation, the farmer’s first reaction has been to take immediate measures of control, leading to indiscriminate use of insecticides.

Consequently, with financing from the Colombian Ministry of Agriculture and Rural Development, a program is being established for the integrated management of the cassava crop’s major pests in the Colombian Departments of Valle del Cauca and Cauca. The aim is to offer different, but efficient, alternatives in pest management, such as biological or microbiological control, varietal resistance, and short-term chemical control, to both small cassava farmers who, until now, have been the major producers of cassava, and larger scale farmers who have not yet obtained much experience.

A diagnosis was first carried out in the study area. The whitefly Aleurotrachelus socialis Bondar was detected as a major pest for which no efficient control was available. In Colombia, whitefly attack is most severe in the Departments of Cauca and Tolima, the Atlantic Coastal Region, and the Eastern Plains, where yields are reduced by as much as 79% in experiment fields. In the Departments of Cauca and Valle del Cauca, the pest has become endemic, affecting the area’s farming economy.

To date, this project has found a native strain of the fungus Verticillium lecanii that can efficiently control the pest, causing high mortality in different A. socialis instars, particularly eggs and second instars.

Expeditions have been carried out in different areas of Colombia, searching for species of the Chrysopa genus (lacewings) that prey on the pest and are considered to comprise a promising alternative for whitefly control. Five native species have so far been identified, and a mass-breeding methodology is being developed.

Chemical control, based on botanical products, was found to be efficient for the small cassava plots cultivated by small farmers, particularly those carrying initial or low populations of the pest. Products traditionally used by farmers, such as methamidophos, dimethoate, and cypermethrin, do not efficiently reduce A. socialis populations, whereas products with different active ingredients such as imidacloprid, thiamethoxan, and diafenthiuron efficiently reduce pest populations. Because these are costly and use different forms of application, they are recommended for larger scale farmers, who have a higher economic capacity.

Because A. socialis is not known to have an alternative host, another, additional, management practice is the “closed season”. At CIAT, experiment fields of cassava are not planted for about 1 month, to break the pest’s cycle.  In following plantings, the pest populations are noticeably diminished.

During the project’s implementation, 400 people have been trained, including farmers and technicians from cassava-growing areas suffering whitefly problems, that is, southern Valle del Cauca, northern Cauca, and Tolima. Training took the form of talks and field days on Aleurotrachelus socialis, discussing the pest’s behavior, damage, and natural enemies, and the different controls available.

Contact: Claudia María Holguín