Abstract

Tomato, Lycopersicum esculentum L. (Solanaceae), is an important vegetable crop in the Mariana Islands (Guam, Saipan, Rota and Tinian). Because tomato is heavily attacked by both the tomato fruitworm Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) and the red spider mite Tetranychus marianae McGregor, research was begun in 2011 to develop an integrated pest management program to better protect the crop from these pests. Our previous studies have indicated nominal threshold levels for T. marianae to be 8-12 mites/leaf in the dry season and 8-14 mites/leaf during the wet season, while for H. armigera the threshold was found to be 2 eggs per 10 of the plants, followed by an additional pesticide application only if 2 damaged fruit or H. armigera larvae were detected per 50 immature fruits. Other studies have found the IPM package used here of petroleum spray oil (PSO), BotaniGard, neem, and DiPel applied 15, 30, 45 and 60 days after tomato transplant to be a viable approach, significantly reducing the pest complex and giving higher tomato yield compared to both the growers’ current practice (carbaryl or malathion, 15 applications per cropping season) and control plots. The current field study was conducted at two locations in Guam (Yigo and Inarajan), USA, in 2012 and 2013 to compare this IPM package with the growers’ current practice in larger plots designed to educate the growers. The IPM package significantly lowered the pest complex and gave higher tomato yield at both the locations. Tomato growers were invited to attend an informal IPM training program on December 16, 2013 at the University of Guam, which was attended by 48 growers from four Mariana Islands. Of these growers, 41 (85%) were aware of and understood the risks associated with traditional insecticides and recognized the concept of using an IPM package in managing tomato pests before the workshop. However, all the attendees understood the concept and benefits of IPM after the workshop. Follow up with these tomato growers found that 35 (73%) later adopted the IPM program using PSO, BotaniGard, and Dipel at 15, 30, 45 and 60 DAT in the Mariana Islands.

Highlights

  • Growers in the Mariana Islands (Guam, Saipan, Rota, and Tinian) have been encouraged to increase vegetable production, including tomato, to reduce the importation of vegetables to the region and avoid the possible introduction of invasive plant and insect species (Reddy & Tangtrakulwanich, 2013).Tomato growers who sell their products to local fresh markets mostly grow cherry tomatoes, which are grown in the Marianas year-round

  • Growers in the Mariana Islands use carbaryl and malathion insecticides to control T. marianae and H. armigera on eggplant and tomato (Reddy & Miller, 2014; Reddy & Tangtrakulwanich, 2013), and as many as 13-15 applications of these pesticides may be applied to each crop, greatly increasing both cost and exposure to pesticide residues

  • The aim of the current study is to compare the relative efficacy of the integrated pest management (IPM) package (PSO, BotaniGard, neem and DiPel), which was found to be effective against T. marianae and H. armigera, with growers’ current practice, to educate growers on the benefits of the IPM package, and to follow up on the rate of adoption of this IPM practice by the growers

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Summary

Introduction

Growers in the Mariana Islands (Guam, Saipan, Rota, and Tinian) have been encouraged to increase vegetable production, including tomato, to reduce the importation of vegetables to the region and avoid the possible introduction of invasive plant and insect species (Reddy & Tangtrakulwanich, 2013).Tomato growers who sell their products to local fresh markets mostly grow cherry tomatoes, which are grown in the Marianas year-round. Growers in the Mariana Islands use carbaryl and malathion insecticides to control T. marianae and H. armigera on eggplant and tomato (Reddy & Miller, 2014; Reddy & Tangtrakulwanich, 2013), and as many as 13-15 applications of these pesticides may be applied to each crop, greatly increasing both cost and exposure to pesticide residues. These applications do not effectively control these pests on tomatoes. To reduce the reliance on miticides and insecticides and to educate the growers about integrated pest management (IPM), a www.ccsenet.org/jas

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