Abstract

SAMANIEGO-GAXIOLA, José Alfredo; RAMIREZ-DELGADO, Manuel; PEDROZA-SANDOVAL, Aurelio  and  NAVA-CAMBEROS, Urbano. Association between cotton root rot (Phymatotrichopsis omnivore) and borer insect of pecan tree (Carya illinoensis). Agric. Téc. Méx [online]. 2008, vol.34, n.1, pp.21-32. ISSN 0568-2517.

Euplatypus segnis (Chapuis) (Coleoptera: Platypodidae) causes severe damage to pecan (Carya illinoensis) trees at Coahuila, Mexico. The present study was carried out during 1999-2001 in a 90 ha pecan orchard, divided in eight lots, during 1999-2001. The trees were counted and clasified in four categories: attacked by borer insects and with symptoms of cotton root rot (Phymatotrichopsis omnivora); only attacked by borer insects: only with symptoms of P. omnivora; and without pest neither disease. The attack by borer insects was significantly more frequent in pecans showing symptoms of P. omnivora than in those without symptoms. The dispersion of the pest adjusted to a Logistic model, with r² values of 0.871, 0.788 and 0.803 in 1999-2001, respectively. The absolute rate of dispersion of the borers was estimated at 2000-1999, 2001-2000 for each lot and year. The highest dispersion rates were observed in coinsidence with a soil moisture deficit in the orchard. The results indicate that frecuency of attack of the borers increases in tress with P. omnivora and irrigation deficit.

Keywords : Cotton root rot; borer insect; pecan tree.

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