Peniocereus serpentinus AND Austrocylindropuntia subulata, NEW HOSTS OF THE CACTUS WEEVIL (Metamasius spinolae Gyllenhal) IN THE STATE OF MEXICO

The cactus weevil (Metamasius spinolae) is a pest of Opuntia ficus-indica. It can develop not only in Opuntia species but also in other cacti and members of the Asparagaceae family. In 2017, damage and presence of adult insects with characteristics similar to the cactus weevil were reported in two species of cacti, Austrocylindropuntia subulata and Peniocereus serpentinus. The objective was to identify the insect and determine if the two cacti species are hosts, field and laboratory research was conducted from 2017 to 2019 in the municipality of Axapusco, State of Mexico. Stems with larval damage were selected at four study sites, whic remained in field conditions until the emergence of adult insects. The behaviour of M. spinolae on the host plant, mating sites, incubation period and damage development over time were recorded. M. spinolae was identified and determined to fulfill its life cycle on A. subulata and P. serpentinus. Larvae cause the most damage by feeding on the internal part (pith) of the stems, which causes tissue rotting and death of the affected part. The adult feeds on tender buds and mature stems, causing deformation and weakening of the plant. The two cacti species proved to be host plants that can harbour populations of M. spinolae and, therefore, have a high potential to act as reservoirs of the pest, which can then migrate to prickly-pear cactus crop. This report expands the knowledge of hosts of the cactus weevil. The information obtained shall be useful for vegetable growers to apply phytosanitary measures in alternate hosts, combat reservoirs and avoid re-infestations of the pest.