The Efficiency of Pest Control Options against Two Major Sweet Corn Ear Pests in China

Simple Summary: Corn ear pests, such as cotton bollworm and corn borer larvae, can infest corn ears within hours to a day, posing a significant challenge for their control. This study aimed to determine the ideal timing for pesticide application, select effective and safe pesticides, and optimize application methods. Over several years, we monitored adult sweet corn ear pests in Beijing, investigating their relationship with corn phenology and local climate to identify the best time for effective pesticide application. Through field experiments evaluating 13 different pesticides, we identified cost-effective and safe options. Ultimately, we discovered that in mid-June, approximately five days after corn silking in sweet corn fields, moth populations got the greatest growth rate. During this crucial period, applying Indoxacarb + Chlorfenapyr, Virtako + mineral oil, or the biopesticide Beauveria bassiana + oil on corn silks and ear surfaces maximized their effectiveness. Our research significantly improves corn ear pest control. Helicoverpa armigera (Hubner) and Ostrinia furnacalis (Guenee) are the most devastating insect pests at the ear stage of maize, causing significant losses to the sweet corn industry. Pesticide control primarily relies on spraying during the flowering stage, but the effectiveness is inconsistent since larvae are beneath husks within hours to a day, making pesticide treatments simpler to avoid. Insufficient understanding of pest activity patterns impedes precise and efficient pesticide control. H. armigera and O. furnacalis in corn fields were monitored in the last few years in Beijing China, and we observed a higher occurrence of both moths during the R1 stage of sweet corn. Moth captures reached the maximum during this stage, with 555-765 moths per hectare corn field daily. The control efficiency of nine synthetic insecticides and five biopesticides was assessed in the field during this period. Virtako, with mineral oil as the adjuvant, appeared to be the most effective synthetic insecticide, with the efficiencies reaching 88% and 87% on sweet and waxy corn, respectively. Pesticide residue data indicated that the corn is safe after 17 days of its use. The most effective bioinsecticide was Beauveria bassiana combined with mineral oil, with 88% and 80% control efficiency in sweet and waxy corn, respectively. These results suggested that spraying effective insecticides 5 days after corn silking could effectively control corn ear pests H. armigera and O. furnacalis. Our findings provide valuable insights for the development of ear pest management strategies in sweet corn.