Conservation Biological Control of Coffee Berry Borer by Applying Nitrogen Fixing Tree Mulch to Enhance Indigenous Entomopathogenic Nematodes

View the project final report

Commodities

• Additional Plants: coffee

Practices

• Crop Production: agroforestry, alley cropping, Reduced pesticide use
• Education and Training: demonstration, extension, workshop
• Natural Resources/Environment: Improve soil health
• Pest Management: biological control, mulches - killed
• Production Systems: agroecosystems
• Soil Management: organic matter, soil microbiology, soil quality/health

Coffee (Coffea arabica) is a high-value commodity, and especially so in Hawaii. Coffee production and sustainability are adversely affected by the Coffee berry borer (CBB), Hypothenemus hampei, as it can cause more than 35% yield loss. Current management practices for CBB include labor-intensive field sanitation and multiple applications of the biopesticide Beauveria bassiana. This project sought to develop sustainable CBB management strategies through a conservation biological control approach that enhanced cosmopolitan soil-dwelling entomopathogenic nematodes (EPN). As soil-dwelling organisms, EPN do not have good mechanisms to protect agains desiccation or UV radiation. These factors limit EPN utility in sustainable IPM practices. However, mulching the soil under the coffee canopy where coffee cherries infected with CBB fall can address these limitations and enhance the efficacy of EPN aginst CBB. Leucaena leucocephala hybrid KX2 or KX4 is a fast-growing nitrogen-fixing tree locally available to farmers, and its chipped mulch is an ideal mulching material for coffee production. Two field trials were conducted to evaluate if Leucaena mulch enhances parasitism of indigenous EPNs on CBB and reduces CBB pressure in the coffee orchard.

Mulching with Leucaena leucocephala KX2/KX4 increased EPN infection of CBB by 1.5 to 2.8 fold in field trails. Inundative release of lab-reared EPN did not increase EPN infection of CBB, regardless if mulch was present or not. Although overall infection of CBB by EPN was 10-23%, mulching may enhance CBB control and aid farmers in reducing fertilizer inputs, as well as improving soil health, which will lead to yield and profitability increases.

The goal of the project was to manage Coffee Berry Borer using entomotatogenic nematodes. The specific objectives were to:

1. Identify indigenous EPN species recovered from coffee orchards on Oahu, Hawaii; 
2. Compare virulence of indigenous EPN strains to Steinernema feltiae and Oscheius tipulae on CBB;
3. Evaluate the efficacy of Leucaena mulch on enhancing EPN infection of CBB; and 
4. Examine the effects of Leucaena mulch on coffee plant and orchard soil health.