Factors affecting the incidence of and damage caused by weevil borers : SRDC final report BS151S

Abstract

This study has shown that sampling billets for weevil borer damage through the extraneous matter system of a sugar mill gives reliable data as it supports in field data collected by BSES. These data may allow the simple field assessments to be related to the entire mill area. This would benefit other mill areas who do not currently sample for weevil borer damage.

The Mulgrave mill data shows high susceptibility to weevil borer by some varieties such as Q113 and Q138 while Q117 has low susceptibility.

There is greater damage in green cane than in burnt cane which reflects historical data. Weevil borers were not a significant problem when pre-harvest burning of cane was standard practice prior to the introduction of green cane harvesting.

By continuing the sampling method undertaken by Mulgrave mill, a good comparison of weevil borer damage across years can be obtained. This may be useful in the long term for predicting weevil borer outbreaks. However, a large amount of data across years are needed to reliably predict outbreaks as damage is dependent on a number of factors such as variety, location and soil type.

By identifying districts and their levels of damage a management strategy for weevil borer control can be implemented.

The sampling method used at the mill changed many times during the season. The most accurate method commenced from week 18 onwards and this may bias the results.