Effect of liquid and solid insecticide applications and insect behavior on Sphenophorus levis Vaurie, 1978 (Coleoptera: Curculionidae) control in sugarcane

• Ano de defesa: 2022
• Autor(a) principal: Ferreira, Pedro Henrique Urach
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Granular; Inseticidas; Cana-de-açúcar; Billbug; Weevil; Ratoon; Residue; Mortality
• Link de acesso: http://hdl.handle.net/11449/236640

Insecticide adoption and current application methods for Sphenophorus levis Vaurie, 1978 (Coleoptera: Curculionidae) control have not been sufficient to reduce insect population due to low insecticide concentrations near the insect as a consequence of its location underneath the soil. Few information regarding the insect’s behavior is currently available and further research must be conducted to assist S. levis management in sugarcane. In addition, conventional control methods are still limited to liquid insecticide applications despite solid applications have proven effective for several soil insects and crops due to gradual insecticide release with a prolonged effect against pests. Therefore, it is extremely important to better understand S. levis behavior and to investigate the potential of solid insecticide applications for S. levis control in sugarcane. The study aimed to assess the repellency of S. levis adults from insecticides and to evaluate adults’ activity and location. In addition, the study’s objective also included evaluating the efficacy of solid and liquid application methods of different insecticides under semi-controlled conditions and field conditions during sugarcane planting and ratoon treatment. The study investigating the insect’s behavior effect was conducted in 2021 and consisted of hourly evaluations of S. levis adults in containers with sugarcane plants and soil. The semi-controlled study was conducted in 2021 and included assessing the mortality levels of S. levis adults with field-simulated applications of liquid and solid insecticides. The three field studies were conducted in 2020 with evaluations in 2020 and 2021 and consisted of assessing S. levis control, sugarcane injury level and sugarcane yield for liquid and solid applications of insecticides (thiamethoxam, fipronil, thiamethoxam + lambda-cyhalothrin, imidacloprid) and one entomopathogenic fungus (Metarhizium anisopliae). S. levis adults were not repelled nor attracted to thiamethoxam + lambda-cyhalothrin treated sugarcane stems and S. levis adults were confirmed to be nocturnal with the greatest number of exposed and active adults occurring from 18:00 pm until 2:00 am. In the field-simulated experiment, low S. levis adult mortality was detected (< 53%) but doubling the solid applied thiamethoxam + lambda-cyhalothrin dosage improved S. levis adult mortality to 76.7%. Regarding the field studies, solid insecticide applications showed great potential for S. levis control improvement in despite of an overall low S. levis control among all treatments. Soil drill applications were seen to promote better efficacy than broadcast and band spraying methods. Insecticide applications at planting and in ratoon cane were not very effective for S. levis control and frequent pest monitoring may help determining the best moment for insecticide application after planting and might help recommending a second application in ratoon cane. Therefore, positive effects from solid insecticide applications were observed indicating potential benefits for S. levis control and the necessity of further studies with appropriate granular formulations with adequate dosages and new insecticides.