We examine the problem of building or fortifying a network to defend against enemy attacks in various scenarios. In particular, we examine the case in which an enemy can destroy any portion of any arc that a designer constructs on the network, subject to some interdiction budget. This problem takes the form of a three-level, two-player game, in which the designer acts first to construct a netwo...

Argumentation, whether philosophical or formal and mathematical, is a discipline of interdisciplinary nature, per se. The recent works on the computational argumentation formalism and their foundations, however, have rested only on logic or logical account. In this paper, we reconsider Dung’s seminal argument acceptability notion in the context of Heider’s socio-psychological balance theory, wh...

Methyl salicylate (MeSA) is a common herbivore-induced plant volatile that, when applied to crops, has the potential to enhance natural enemy abundance and pest control. The impacts of MeSA in strawberry were unknown and examined in the spring and midsummer period. Strawberry plots contained no lures (control) or two 30-d MeSA lures (Predalure) in the center: one lure 0.61 m aboveground over a ...

Edge effects in fragmented natural habitats may De exaceroateci by intensive land use in the surrounding landscape. Given that most managed systems have higher primary productivity than adjacent natural systems, theory suggests that bottom-up subsidized consumers are likely to spill over from managed to natural habitats. Furthermore, the magnitude of spillover is likely to differ between genera...

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is considered a key citrus pest due to its role as vector of 'huanglongbing' (HLB) or citrus greening, probably the most economically damaging disease of citrus. Insecticidal control of the vector is still considered a cornerstone of HLB management to prevent infection and to reduce reinoculation of infected trees. The severity of HLB ha...

The sorghum ( Sorghum bicolor [L.]) agroecosystem of North America provided an opportunity to evaluate response invading insect herbivore, Melanaphis sorghi (Theobald) (sorghum aphid) (previously published as sacchari Zehntner) (Hemiptera: Aphididae) onto a widely planted crop that experiences range agro-landscape and weather conditions. Initial risk assessments after M. 's invasion in the mid-...

Farms benefit from pest control services provided by nature, but management of these services requires an understanding of how habitat complexity within and around the farm impacts the relationship between agricultural pests and their enemies. Using cage experiments, this study measures the effect of habitat complexity across scales on pest suppression of the cabbage aphid Brevicoryne brassicae...

A 6-yr Þeld study assessed the long-term impact of Bt cotton producing the Cry1Ac -endotoxin on 22 taxa of foliar-dwelling arthropod natural enemies inArizona. No chronic, long-term effects of Bt cotton were observed over multiple generations of nontarget taxa. Zero-2 taxa declined signiÞcantly in unsprayed Bt compared with non-Bt cotton each year. In contrast, positive control studies showed t...

Mango mealybug, an exotic pest of mango, was first observed in Benin in 1986. In a biological control programme, natural enemies were successfully released in the following years. The present study is the first attempt to measure the impact of the biological control of mango mealybug over a large area, through a survey of mango producers. Most producers attributed the observed improvement of ma...

While plants are invariably attacked by numerous insects and pathogens, the consequences of multiple enemies for plant performance are poorly understood. In particular, a predictive framework is lacking for when to expect enemies to have independent versus non-independent effects on their host plant. This is problematic for weed biological control programmes where multiple enemies are frequentl...