Module of Integrated Insect Pest Management on Tomato With Growers’ Participation

  •  Gadi Reddy    
  •  Khanobporn Tangtrakulwanich    


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.

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