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Integrated stem borer management in smallholder coffee farms in India, Malawi and Zimbabwe

Funders

Common Fund for Commodities (CFC) with co-financing and counterpart contributions from national programmes.

Partners

International Coffee Organisation (ICO) (Supervisory Body), Natural Resources Institute (NRI) (Assisting Agency), Coffee Board of India, Coffee Research Centre (Chipinge, Zimbabwe), Lunyangwa Research Station (Malawi)

Project Description


Larva of African coffee stem borer showing damage to coffee tree

Problem/Issue. The coffee white stem borer (Xylotrechus quadripes) is a widespread pest of coffee in both Africa and Asia, causing severe economic losses.

Damage is caused by the larvae of these cerambycid beetles, which feed just under the bark, which splits to make the stem appear ridged. Later, larvae enter the hardwood and tunnel in all directions, even into the roots.

Infested trees normally have yellow, wilting leaves, and frass ejected by the wood-boring phase and emergence holes can be found on the stems. Severe ring barking of the main roots occurs below ground level, and extends above ground in rejuvenated coffee.

Attack often results in the death of 1- to 2-year-old coffee trees and severe wilting of 3- to 4-year-old trees. Mature trees are not necessarily killed but, especially in Africa, they become susceptible to termite attack, particularly in the absence of irrigation during the dry season. In general, white stem borer infested trees are of poor vigour and yield poorly.

Stem borers have cumulative impact. In addition to crop losses, investment is needed to replace uprooted trees and as these take time to come into production, the effects of borer damage are felt for at least 5 years.

  • For Malawi, coffee is currently the fourth most important export earner. Stem borers are undoubtedly the major pest constraint for smallholder coffee farmers, with incidence exceeding 90%, and 90% of coffee farmers rating it as their most important pest;
  • In Zimbabwe the borer has led to the uprooting and subsequent replanting of many plantations;
  • In South India the borer has been found in the coffee estates for more than a century and it is the most destructive pest of arabica coffee in the country. Uprooting one plant per hectare per year accounts for an annual loss of about US$8-10 million. Because of the borer, there is a growing trend to convert from arabica to robusta, which would affect export earnings.

Coffee is currently in oversupply and high consumer stocks exacerbate the situation. Quotas have been abandoned and retention schemes are unlikely to take effect. Overproduction is likely to continue since mechanization of plantations is increasing and keeping prices weak. Smallholder livelihoods are under threat as never before, and if the smallholder farming sector is to survive and compete with large plantations, it needs help to solve problems and develop new strategies.

In such prevailing conditions, smallholder farmers tend to reduce all inputs including pest control efforts, which leads to reduced quality and quantity, thus further affecting their economic position. The best response to the situation, however, is to concentrate on increasing quality, and adopt tactics that help reduce inputs of dangerous and costly chemicals. Such a strategy will also facilitate entry to new markets, which pay more for environmentally friendly, sustainably produced coffees. This project aims to help them achieve this, and protect them from any future claims that they are insensitive to the increasing environmental awareness of consumer countries.

Measures to Date. Current management strategies are generally ineffective, or rely on undesirable chemical applications. Cultural control methods include uprooting and burning infested trees, treating the stems during the oviposition period to kill or dislodge eggs and young larvae, catching and killing adults during their period of activity, and maintaining shelter belts in order to shade the coffee bushes, as plants exposed to sunlight are more at risk.

Chemical control includes treatment of stems and primary branches with BHC to reduce the incidence of attack. Biocontrol of X. quadripes in Vietnam during the 1920s involved mass-releases of the two most easily reared parasitoids found in plantations (Doryctes strioliger and Sclerodermus domesticus). The resultant increase in parasitism rates was not maintained after releases ceased. The work was abandoned owing to the high cost of developing a continuous mass rearing programme.

Current management techniques under trial on a local basis include:

  • Maintaining optimum shade;
  • Tracing infested plants before flight periods each year, collar pruning infested plants are collar pruned (uprooting if the borer has entered the root), and burning pruned material;
  • Removing loose scaly bark of the main stem and thick primaries using coir glove or coconut husk, but avoiding damage to the stem;
  • Spraying/swabbing the main stem and thick primaries during flight periods with Lindane and a wetting agent.

Project Activities. The aim of this project is to develop and implement new ways of controlling stem borers, focusing on methods that are designed to be environmentally friendly, non-toxic, and cheap enough to be within the reach of smallholder coffee farmers. This will enable farmers to more sustainably maintain their coffee without recourse to expensive replanting or control measures.

As white stem borer is the major constraint to the production of arabica coffee in India, Zimbabwe and Malawi, there is urgent need to evolve an effective integrated management package. Immediate objectives are therefore to:

  • Identify shortcomings and optimise present practices with currently available technology, involving national programmes and coffee farmers;
  • Develop new technologies in pest management, especially biocontrol agents and other biologically-based methods such as pheromones;
  • Train extension workers in farmer participatory extension programmes;

Specific objectives involve:

  • A baseline socio-economic survey to review present practices, their cost-effectiveness, level of uptake by farmers and their problems and perceptions;
  • A biological survey to quantify the effect of agricultural and environmental parameters on incidence of coffee stem borers and their natural enemies;
  • Screening coffee varieties to ascertain resistance to borers;
  • Identifying and evaluating the potential of natural enemies of coffee stem borers, and initiating rearing programmes;
  • Establishing field trials, with farmer participatory research approaches, to quantify efficacy of potential control methods, including improved agronomic practices, safer pesticides, botanical repellents and pheromones;
  • Developing and facilitating improved extension mechanisms through training of trainers and extensionists to enable technology transfer using farmer participatory approaches.

Achievements So Far

The CFC approved funding for the project totalling US$2.26 million in October 2001 (of total project value of US$3.1m), subject to final signing of Project Agreements. This has now been completed and the project commenced in mid-July 2002.

What Next

An inauguration workshop will be held, most probably in India, in September 2002.

Dr. Peter Baker (International Co-ordinator) p.baker@cabi.org
Dr. Sean Murphy (India Co-ordinator) s.murphy@cabi.org
Dr. George Oduor (Africa Co-ordinator) g.oduor@cabi.org
Simon Lea (Administrator) s.lea@cabi.org

Start: July 2002

End: 2006

 
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Contact CABI Commodities:
CABI Commodities Coffee Co-ordinator - Dr. Peter Baker - p.baker@cabi.org
CABI Commodities Cocoa Co-ordinator - Dr. J. Flood - j.flood@cabi.org
CABI Commodities Project Administrator - cabi-commodities@cabi.org