Identification of White Grub (Coleoptera: Scarabaeidae) Genera and Species that Cause Damage in Broccoli, Guatemala, 1997
Humberto Carranza Bazini, Albaro Orellana Polanco, Danilo Dard?n Avila (Guatemala); Stephen Weller (US)
In Guatemala white grub (Coleoptera: Scarabaeidae) causes serious losses in traditional and non-traditional crops. Farmers and exporting companies alike complain about the many losses caused by this pest. White grub genus and species that damage broccoli in different farming zones, are identified in this study. Losses are estimated with information provided by the farmers and through field surveys estimating the incidence (% infested plants) conducted by the research team. The study took place in the departments of San Marcos, Huehuetenango, Quetzaltenango, Solol?, El Quich?, Chimaltenango, Guatemala, Jalapa, Baja y Alta Verapaz. Sample collection took place during the months of August to November of 1996.
The study determined that the most commonly found genera in larval state, in broccoli, were Phyllophaga sp. (70.97%) and An?mala sp. (24.30%) which are both phytophagous species. Other species were Cyclocephala (4.24%) and Lygyrus (0.47%), both harmless to the broccoli plants. Phyllophaga species found in the larval stage were P. obsoleta (71.63%), P. menetriesi (9.02%), P. valeriana(8.32%), P. elenans(2.28%) and P. zunilensis (0.92%). In adult specimens, Phyllophaga and Anomala were determined through specific white grub keys, both were also identified at the larval stage. From a total of 10 adult Phyllophaga specimens, 8 were P. obsoleta, 1 was P. tumultosa, and 1 specimen of P. rufotestacea (not known as plant pest). Farmers in our survey estimated that white grub damage can occasionally reach 100%. Damage estimates by the research team in the direct surveys varied between 1% and 95% with a national mean of 25%.