Anatomical and Physiological Alterations in the Sugarcane Leaf Due to Sugarcane Rust Mite Feeding

The sugarcane rust mite (SRM), Abacarus sacchari (Channabasavana), has been reported in Florida for decades; however, the information about the impact of the mites’ feeding is very limited. We investigated the effects of SRM feeding activity on the sugarcane leaf ultrastructure and physiology in a sugarcane field within three consecutive cropping cycles with manipulation of the SRM population using acaricide applications. The experiment was arranged in a two-factorial randomized complete block design using acaricide application as the main plot treatment, three sugarcane genotypes, namely CP88-1762, CP89-2143, and CP00-1101 as the subplot treatment. The study showed that sugarcane genotypes responded differently to SRM attacks, with CP89-2143 displaying the most obvious symptoms. The injury due to SRM feeding could reach the leaf tissues deep under the epidermal layer and ultrastructure alterations were detected on the affected leaves. Furthermore, SRM could change leaf morphology and anatomy, leading to a reduction in chlorophyll content of up to nearly 20% and a photosynthetic rate of up to 20% in the most susceptible genotypes studied