Summary
No significant correlations were detected in the survey of the Louisiana sugarcane
industry in 2000 and 2001 between seasonal rainfall events and insecticide application
frequency, spring deadhearts, or end-of-season bored internodes. However, in the areas that had
early rainfall and continued to receive frequent rains throughout the season, a higher use rate of
insecticide was used and frequently a higher percentage of end-of-season bored internodes were
encountered. The information provided by the survey concerning the association between
amounts of rainfall and sugarcane borer infestations throughout the season seemed to be accurate
based upon empirical data gathered by the author during the 2003 sugarcane production season.
The industry experienced early rains in April and May, which was followed by constant rainfall
in the production months of June, July, and August. Many producers averaged between one and
two applications, and a few growers made three applications.
In the sugarcane borer management study, results from the plant cane crop (2001) and
from the first ratoon crop (2002) showed no differences among different variety-management
threshold strategies, except for significantly lower percent bored internodes for the treated
regimes compared to the non-treated regimes. However, the threshold management regimes
varied insecticide application frequency to maintain sugarcane borer infestations below the
designated thresholds.
TRS was significantly different between the treated regimes (5%, 5%/10%, and 10%) and
the non-treated regime, and illustrates the economic value of treating sugarcane borer
infestations with insecticides. According to this study, a grower could justify two applications of
insecticides plus the cost of the consultant for control of the sugarcane borer and have around
four dollars/ha remaining in the budget versus not treating and suffering losses due to a decline
in TRS at a cane yield of 69.5 metric tons per hectare.