Sugarcane Planting Date Impact on Fall and Spring Sugarcane Borer (Lepidoptera: Crambidae) Infestations
In a two-year field study, sugarcane was planted on 4 dates ranging from the first week of Aug to the third week of Nov, reproducing sugarcane phenologies associated with planting and harvesting operations in Louisiana. Sugarcane planted in early Aug offered an extended period of plant availability for sugarcane borer, Diatraea saccharalis (F.), infestations during the fall. Periodic sampling throughout the fall showed that early Aug plantings had higher (P < 0.05) D. saccharalis-caused deadheart densities than later planted sugarcane. Destructive sampling conducted in early Oct showed that Aug plantings harbored greater deadheart densities (P < 0.05 in fall 2007) and D. saccharalis infestations (P < 0.05 in fall 2006 and 2007) than Sep plantings. Data from this study suggest a potential for increased D. saccharalis overwintering populations in early plantings associated with greater infestations during the fall. However, differences in deadhearts and D. saccharalis infestations in deadhearts were not detected (P > 0.05) during the spring. Three commercial sugarcane cultivars (‘L 99-226’, ‘L 97-128’, ‘HoCP 95-988’) were studied. Differences in D. saccharalis injury or infestations as affected by cultivar were detected (P < 0.05) only in early Oct 2007 when ‘HoCP 95-988’ harbored 2.3-fold greater infestations than ‘L 99-226’.