▪ Abstract In this article we consider the role of epidemiological factors and transmission processes of insect-vectored viruses on the effectiveness of insecticides in a disease management program. We also discuss the use of insecticides within the broader framework of the chemical environment surrounding vectors, and how chemical-induced alterations in the behavior of vectors can influence transmission. Our analysis confirms the belief of Heathcote, who stated in 1973, that “no one method of control is likely to keep crops entirely free from virus infection and as many preventative measures should be taken as are economically justified.”
The painted bug, Bagrada hilaris, native to eastern and southern Africa and Asia, was detected in California in 2008, and it has spread rapidly throughout several southwestern US states. A polyphagous insect, it is particularly damaging to the billion dollar cole crop industry. B. hilaris frequently causes damage when it migrates to newly planted crops from weedy hosts. Feeding produces circular or star-shaped chlorotic lesions that become necrotic, and infested plants may be distorted. Currently, no reliable sampling methods for B. hilaris exist, nor are there effective natural enemies in the United States. Therefore, management has relied on multiple applications of insecticides and cultural practices such as removal of weedy hosts, destruction of crop residues, timing of planting, and use of transplants. Several pyrethroid and neonicotinoid insecticides are most effective for controlling the insect. Reliable sampling methods and further development of integrated pest management strategies to manage this invasive pest are urgently needed as its range continues to expand.
1 September 2013 in Journal of Integrated Pest Management
This chapter explores the literature on Bagrada hilaris pertaining to its systematic and taxonomic history and identification, worldwide distribution, basic biology, host range, and impact and management in agricultural systems. Bagrada hilaris, the painted bug, is known throughout the world as a serious pest of vegetable crops, particularly plants in the family Brassicaceae. The rapid range expansion of Bagrada hilaris in the New World, combined with the continuing pest status and expansion in the Old World, has generated considerable research efforts, particularly aimed at mitigating losses in agriculture. Organic producers have limited control strategies, and both organic and conventional growers are changing their growing practices due to damage by B. hilaris. For example, organic growers are altering planting schemes and timing to avoid painted bug infestations, and large farm growers have begun to use transplanted cole crops rather than direct seeding. Bagrada hilaris with its red, black, orange, and white markings easily is distinguished from most other pentatomids.
Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae) is a non-native stink bug that feeds primarily on cole crops and wild mustards. Its invasion into desert agriculture in California and Arizona presents a conundrum between rapid pest development at warm temperatures and severe damage to cool season crops. In this study, the development and survival of B. hilaris were determined at nine constant temperatures (ranging from 20–42°C) when reared on organically grown broccoli florets. Egg hatching was greatly delayed at 20°C, and first instar nymphs did not survive at this temperature. No eggs hatched at 42°C. The highest survival rates (70.0–86.7%) of B. hilaris were observed at temperatures ranging from 24 to 35°C. The total developmental rate of B. hilaris from egg to adult increased from 0.027 to 0.066/d from 24 to 35°C, and then slightly dropped to 0.064/d at 39°C. Based on the linear model, B. hilaris requires 285.4 degree-days to complete its development. The Briere 1 model predicted the lower and upper temperature thresholds as 16.7 and 42.7°C, respectively. The optimal temperature for development (TOpt) was estimated as 36°C. According to the results, B. hilaris is well adapted to warm conditions, and temperatures of 33–39°C are well suited for B. hilaris development. Information from this study helps explain the rapid range expansion of B. hilaris across the southern United States and will be instrumental in predicting future expansion across the rest of the country and in other parts of the world. The relationship between thermal thresholds and invasion dynamics of this pest are discussed.