VL Lauchande1,2, LN Malinga1,2 and TC Munyai2
1South African Sugarcane Research Institute, Mount Edgecombe, South Africa; vanessalauchande@gmail.com
2School of Life Sciences, University of KwaZulu-Natal, Scottsville, South Africa
In South Africa, the lepidopteran stem borer Eldana saccharina is one of the most important pests of sugarcane. The cryptic nature of E. saccharina has limited previously used management strategies and has spurred researchers to investigate newer methods. This study evaluates the synergistic effect of genetically modified (GM) sugarcane expressing Bacillus thuringiensis (Bt) toxins and the sterile insect technique (SIT) in managing E. saccharina. Stalk damage was assessed on 12-month-old non-Bt (88H0019) and Bt sugarcane (GM CRY1A transformed from 88H0019) grown in a treatment (SIT included) and control (SIT excluded) shade house. Internode damage (%INB), stalk bored length (%SLD), stalk red length (%SRL) and infestation rates per 100 stalks (e/100) were assessed. The study yielded limited results. However, some reasonable assumptions were drawn. Sterile moth releases failed to significantly reduce stalk damage (p>0.05), with the highest stalk damage being observed in the treatment shade house. However, significantly lower (p<0.05) damage was found on GM CRY1A sugarcane in both shade houses with the lowest %SLD, %INB, and %SRL. In addition, infestations differed (p<0.05), with 88H0019 sugarcane displaying higher infestation rates (3.686 e/100) than GM CRY1A (0.160 e/100). While SIT may not directly mitigate stalk damage, integrating Bt sugarcane effectively suppresses E. saccharina populations and related damage. Future research should focus on optimizing SIT application to enhance its efficacy in pest management alongside genetically modified crops, highlighting the importance of an integrated approach in sustainable agriculture.