Effect of vegetation diversity on natural enemy abundance in two agricultural contexts

© 2012 Purabi R. GhoshVegetation diversity has long been known to enhance natural pest control at both the local and landscape level. However little is known about the characteristics of this vegetation that promote/shelter more natural enemies and suppress pests. The main aim of this thesis was to examine how characteristics of common non-crop vegetation influence the abundance, diversity and association of natural enemies residing in two different agricultural systems (canola fields and vineyards). These crops were chosen to contrast annual and perennial cropping systems. Canola, grown directly after a pasture phase of a field, is Australia’s most important oilseed crop. Pressure on invertebrates may be greater due to level of disturbance; in contrast, vineyards are often surrounded with various types of vegetation which may enhance invertebrate abundance. To explore this aim, the effect of within crop, non-crop vegetation (grass strips within canola crop) on abundance of pests and natural enemies in the crop was examined. Invertebrates were collected across grass-canola transects in two fields planted to canola with unsown grass strips at intervals. Sampling with pitfall traps and vacuum sampling was completed to collect ground dwelling fauna during two sampling periods: post sowing and post emergence of canola seeds. Invertebrates collected were categorized mainly into two groups: pests and natural enemies. Abundant pests in the canola fields were red legged earth mite, Halotydeus destructor; blue oat mites, Penthaleus spp. and lucerne flea, Sminthurus viridis. Natural enemies considered were spiders (Araneae), predatory mites (Acari), predatory beetles (Coleoptera) and parasitoids (Hymenoptera). In general more predators and parasitoids were found in the unmown grasses of grass strips and more pests in mown sections of the grass strips and overall pests were more abundant in the crops than in grass strips. Vegetation types may have different influences on the biota that reside within them. Thus the effectiveness of different vegetation types in promoting conservation biological control was assessed at vineyards with two types of non-crop habitat: adjacent- grass with and without trees. Invertebrates were sampled in the canopy with sticky traps and on the ground with pitfall traps at 40 sites from six different vineyards at Yarra Valley (Victoria) for five consecutive months from bud burst to harvest (October through February). Collected invertebrates were classified as natural enemies and other invertebrates since none of the invertebrates collected are considered as pests in vineyards. The most abundant natural enemies were generalist predators (spiders and predatory beetles Coleoptera: Carabidae and Staphylinidae) and parasitoids (Hymenoptera), lacewings (Neuroptera), hover flies (Diptera: Syrphidae) and other predatory Diptera (Asilidae, Empididae and Tachinidae), predatory thrips (Thysanoptera), predatory Hemiptera, and ladybird beetles (Coleoptera: Coccinellidae). Other invertebrates analyzed included several other beetle families, thrips (Thysanoptera) and several herbivore families of Hemiptera. Overall no effect of vegetation diversity was identified in this study though a significant vineyard effect was revealed for most of the natural enemies and other invertebrates

Effect of vegetation diversity on natural enemy abundance in two agricultural contexts

© 2012 Purabi R. GhoshVegetation diversity has long been known to enhance natural pest control at both the local and landscape level. However little is known about the characteristics of this vegetation that promote/shelter more natural enemies and suppress pests. The main aim of this thesis was to examine how characteristics of common non-crop vegetation influence the abundance, diversity and association of natural enemies residing in two different agricultural systems (canola fields and vineyards). These crops were chosen to contrast annual and perennial cropping systems. Canola, grown directly after a pasture phase of a field, is Australia’s most important oilseed crop. Pressure on invertebrates may be greater due to level of disturbance; in contrast, vineyards are often surrounded with various types of vegetation which may enhance invertebrate abundance. To explore this aim, the effect of within crop, non-crop vegetation (grass strips within canola crop) on abundance of pests and natural enemies in the crop was examined. Invertebrates were collected across grass-canola transects in two fields planted to canola with unsown grass strips at intervals. Sampling with pitfall traps and vacuum sampling was completed to collect ground dwelling fauna during two sampling periods: post sowing and post emergence of canola seeds. Invertebrates collected were categorized mainly into two groups: pests and natural enemies. Abundant pests in the canola fields were red legged earth mite, Halotydeus destructor; blue oat mites, Penthaleus spp. and lucerne flea, Sminthurus viridis. Natural enemies considered were spiders (Araneae), predatory mites (Acari), predatory beetles (Coleoptera) and parasitoids (Hymenoptera). In general more predators and parasitoids were found in the unmown grasses of grass strips and more pests in mown sections of the grass strips and overall pests were more abundant in the crops than in grass strips. Vegetation types may have different influences on the biota that reside within them. Thus the effectiveness of different vegetation types in promoting conservation biological control was assessed at vineyards with two types of non-crop habitat: adjacent- grass with and without trees. Invertebrates were sampled in the canopy with sticky traps and on the ground with pitfall traps at 40 sites from six different vineyards at Yarra Valley (Victoria) for five consecutive months from bud burst to harvest (October through February). Collected invertebrates were classified as natural enemies and other invertebrates since none of the invertebrates collected are considered as pests in vineyards. The most abundant natural enemies were generalist predators (spiders and predatory beetles Coleoptera: Carabidae and Staphylinidae) and parasitoids (Hymenoptera), lacewings (Neuroptera), hover flies (Diptera: Syrphidae) and other predatory Diptera (Asilidae, Empididae and Tachinidae), predatory thrips (Thysanoptera), predatory Hemiptera, and ladybird beetles (Coleoptera: Coccinellidae). Other invertebrates analyzed included several other beetle families, thrips (Thysanoptera) and several herbivore families of Hemiptera. Overall no effect of vegetation diversity was identified in this study though a significant vineyard effect was revealed for most of the natural enemies and other invertebrates

Progress towards Sustainable Utilisation and Management of Food Wastes in the Global Economy

In recent years, the problem of food waste has attracted considerable interest from food producers, processors, retailers, and consumers alike. Food waste is considered not only a sustainability problem related to food security, but also an economic problem since it directly impacts the profitability of the whole food supply chain. In developed countries, consumers are one of the main contributors to food waste and ultimately pay for all wastes produced throughout the food supply chain. To secure food and reduce food waste, it is essential to have a comprehensive understanding of the various sources of food wastes throughout the food supply chain. The present review examines various reports currently in the literature and quantifies waste levels and examines the trends in wastage for various food sectors such as fruit and vegetable, fisheries, meat and poultry, grain, milk, and dairy. Factors contributing to food waste, effective cost/benefit food waste utilisation methods, sustainability and environment considerations, and public acceptance are identified as hurdles in preventing large-scale food waste processing. Thus, we highlight the need for further research to identify and report food waste so that government regulators and food supply chain stakeholders can actively develop effective waste utilisation practices