Effectiveness of Beauveria bassiana on coffee berry borer in different agroclimatic zones

View the project final report

Commodities

• Fruits: general tree fruits

Practices

• Education and Training: demonstration, extension, mentoring, on-farm/ranch research, participatory research, workshop
• Pest Management: biological control

The coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae) is the most economically important coffee pest worldwide due to the extensive destruction on the coffee seed that they inflict. This beetle reduces yields and quality of coffee, resulting in reducing the income of coffee growers and the sustainability of coffee producing areas. In August 2010, the coffee berry borer was reported in South Kona, Island of Hawaii. The infestation has since extended, and the beetle is now present from North Kona to the district of Kau on east side of the island, and it is severely impacting farms and mill operators. Several farmers have stumped their coffee trees due to the devastating level of infestation. Economic losses for the region have been reported to exceed 60%. 2011 showed a significant increase in CBB damage compared with the 2010 harvest. Reports from the processing mills in Kona estimated the harvest losses to be over 60%. It is only a matter of time before the pest finds its way to other Hawaii coffee growing areas on Oahu, Maui and Kauai.

Owing to the fact that the coffee berry borer has only recently invaded Hawaii, management techniques are limited, and there is urgency for a strategic plan to reduce populations. The insect-pathogenic fungus, Beauveria bassiana (formulated a Botanigard, Mycotrol O) was licensed for use in February 2011 by the Hawaii Department of Agriculture (HDoA) and is the only commercial pesticide product available to manage the coffee berry borer in Hawaii. This fungus has shown to cause high mortality of the coffee berry borer in Latin America. In Hawaii, B. bassiana is sprayed on a calendar basis, without any science-based data upon which to base decisions on when to make applications. Frequency of application and timing of first applications are thus made arbitrarily. Kona coffee is grown at different elevations, ranging from 213 m to 609 m above sea level, and fruit production is all perennial, which facilitates the establishment and reproduction of the coffee berry borer and results in frequent fungus applications as growers are concerned that they will incur complete crop losses. These factors clearly show the need to achieve a greater understanding of the effect of B. bassiana on the coffee berry borer, with special reference to timing of applications and the effects of local environmental conditions on the effectiveness of the product.

1) To determine the effective dose of B. bassiana as a control measure for the CBB at different agroclimatic zones in Kona,

2) evaluate the fungal infection after the first application to determine the time for future applications, and

3) disseminate and publish the results of this study.

Three months after flowering (April or June 2012), presence of coffee berry borer will be assessed in five coffee farms located at different elevations (140, 344, 368, 535 and 700 m) in Kona. We will use Botanigard®, the commercial strain of B. bassiana. Botanigard® will be mixed with water and Widespread Max that is the recommended adjuvant for Botanigard® that serves as spreader. Beauveria bassiana will be sprayed approximately two months (April or June) after flowering, which is the time when CBB starts infesting the coffee berries. Based on label instructions, Botanigard® will be sprayed at its maximum, medium and lower recommended doses. A randomized block experimental design will be established at each farm with four treatments of 16, 24 and 32 oz of Botanigard® and the control. On each farm, there will be three replicates of each treatment. The experimental unit will be one plant with four plants per replicate. Each plant will be marked with a color ribbon to facilitate identification. Before the application of Botanigard®, a sample of coffee beans will be taken to determine the infestation level of CBB. Botanigard® will be applied early in the morning (6:00 to 8:00 am or late evening 5:00 to 7:00 pm) with a calibrated backpack sprayer. Coffee plants will be sampled for CBB infestation every 10 days for two months after treatment application. Sampling will be carry out using the middle part of each plant, which will be sampled by selecting four branches on the four cardinal points. For each sample, the following factors will be measured: the total number of berries on each branch, the number of berries infested by the CBB and number of fruits infested by the CBB and showing signs of fungus at the entrance of the perforation. Fruits with the fungus will be marked with paint to identify them in subsequent samples. Eight infested berries with fungus present will be sampled for each plot, dissected and dead females will be isolate individually in Petri dishes with Potato Dextrose Agar to confirm the presence of B. bassiana. A rain gauge and a hydrothermograph will be installed at each coffee plantation to record rainfall, temperature and relative humidity. The data will be analyzed using univariate statistics. Three workshops will be held (two in Kona and one in Kau district) to educate farmers about the experiment and its results. These workshops will be arranged by the extension agent specializing in Kona coffee and in collaboration with the coffee associations. Results will be posted at the College of Tropical Agriculture and Human Resources (CTAHR) website and published in a peer-reviewed entomology journal.