The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a widespread pest species of various cultivated plants. The pest status of FAW in cotton in the Cerrado region of Brazil has increased with the recent changes in cotton crop systems, such as double cropping and the use of cover or winter crops with non‐tillage cropping systems. In this study we investigated the performance of FAW on three major crops cultivated in the Cerrado – soybean, corn, and cotton – and millet which has been integrated into the landscape as a cover crop. Further, the damage to various reproductive structures of cotton plants by FAW larvae was determined. Both studies were conducted under field conditions. Survival of FAW larvae caged on millet plants was higher than on other hosts. The FAW reared on millet also exhibited a net reproductive rate similar to that observed on corn, which was considered the best host for FAW, and the highest intrinsic rate of increase and lowest mean generation time compared to all other hosts. In cotton, the low availability of bolls during the plant’s blooming stage resulted in higher square feeding, whereas infestation during the plant’s boll stage resulted in higher loss of bolls and lower attack on squares. The number of adults produced in a generation was higher when plants were infested in the boll stage. The results indicated that FAW is a threat to cotton when bolls are available and can cause significant loss of reproductive structures. In addition, based on the FAW performance feeding on millet, this cover crop can be among the reasons of FAW increasing pest status in subsequent crops.
The coccinellid Tenuisvalvae notata (Mulsant) (Coleoptera: Coccinellidae) has been observed recently in association with the striped mealybug Ferrisia virgata Cockerell (Hemiptera: Pseudococcidae) and the false cochineal scale Dactylopius opuntiae Cockerell (Hemiptera: Dactylopiidae) in the semiarid region of Pernambuco, Brazil. The latter species are important pests of cotton and prickly pear, respectively. In this study, we tested the two scale insects as prey for T. notata. In addition, eggs of Anagasta kuehniella Zeller (Lepidoptera: Pyralidae) were tested as possible alternative prey for rearing T. notata. In this work, the survivorship, reproduction, and predation of T. notata were investigated. The coccinellid T. notata was able to complete development only on F. virgata with 83% larval and pupal viability. Females of T. notata fed F. virgata produced 7.6 eggs a day with an eclosion rate of 61.9%. No oviposition occurred while feeding on A. kuehniella eggs. The highest consumption rate of F. virgata occurred during the last larval instar. Our results support the use of T. notata as an agent for the biological control of F. virgata, a highly polyphagous pest worldwide.
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