Understanding changes in farmers’ knowledge, attitudes, and practices after releasing <i>Acerophagus papayae</i> (Hymenoptera: Encyrtidae), a biocontrol agent for papaya mealybug (<i>Paracoccus marginatus</i>) (Hemiptera: Pseudococcidae) in Kenya

BackgroundFarmer perceptions are highly important in influencing on-farm pest management decision-making. Biological control is extremely sustainable in the smallholder production context, but in Sub Saharan Africa (SSA) few attempts using this pest control method for arthropod pests have been successful, with one of the key reasons cited as poor involvement of farming communities and extension in the dissemination of information. Although farmers’ knowledge and attitudes are hugely important for the successful implementation of biological control, they are often disregarded. Papaya mealybug (Paracoccus marginatus) (PMB) has rapidly spread and established in suitable areas across Kenya becoming a serious pest. The objective of this study is to determine smallholder farmers’ knowledge, attitudes and practices towards biological control; farmers’ willingness to reduce their chemical pesticide use; and levels of support for a classical biological control initiative for PMB management.MethodsHousehold surveys were conducted covering 383 farming households (148 women) in four papaya producing counties in Kenya alongside key informant interviews with eight extension agents and thirty agro-dealers, and eight focus group discussions.ResultsAlthough some farmers demonstrated awareness of the concept of biological control they lacked knowledge, experience and technical support from extension or agro-dealers. Reasons for not using biological control included inadequate awareness and concerns over efficacy and safety. Farmers expressed high levels of interest and willingness to support biological control, and were willing to reduce their chemical pesticide use to help conserve, and support the establishment of natural enemies. County, perception of biological as safe, training in IPM and gender were all highly significant factors determining farmers willingness to support biological control.ConclusionsPreviously, poor attention has been paid to farmer perceptions and participation in biological control, which has resulted in limited success in developing countries. With high levels of interest and willingness to support biological control, the next step is to engage with farming communities impacted by PMB. By building awareness and capacity, and developing a management plan with farmers that will support the release and establishment of the biological control agent, Acerophagus papayae, long-term, sustainable control of PMB in Kenya is possible.

Beauveria bassiana is one of the insect pathogens that can be used as a biological control agent. The interaction between Beauveria bassiana and other natural enemies in biological control can affect the effectiveness of pest control as a biopesticide. The efficacy of these fungi was also influenced by the toxin produced (beauvericin, bassianin, bassiacridin, beauvericin, bassianolide, cyclosporine, oosporein, and tenellin) which may interfere the nervous system and kill the target insects. The use of chemical pesticides, which has been one of the farmers’ choices in pest control, has negative impacts on the environment, human health, and pest resistance therefore, B. bassiana as an alternative, biological pest control and biological control are increasingly considered as environmentally friendly and sustainable control methods, so that biological control can become an important alternative to reduce the use of chemical pesticides. Facing this problem, alternative methods including the use of entomopathogenic fungi as biopesticide could be a sound measure to preserve the environment, biodiversity and ensure good quality of crops.

The biopesticide market for global agricultural use

Biological control is an underlying pillar of integrated pest management, yet little focus has been placed on assigning economic value to this key ecosystem service. Setting biological control on a firm economic foundation would help to broaden its utility and adoption for sustainable crop protection. Here we discuss approaches and methods available for valuation of biological control of arthropod pests by arthropod natural enemies and summarize economic evaluations in classical, augmentative, and conservation biological control. Emphasis is placed on valuation of conservation biological control, which has received little attention. We identify some of the challenges of and opportunities for applying economics to biological control to advance integrated pest management. Interaction among diverse scientists and stakeholders will be required to measure the direct and indirect costs and benefits of biological control that will allow farmers and others to internalize the benefits that incentivize and accelerate adoption for private and public good.

Landscape heterogeneity affects arthropod functional diversity and biological pest control

Opportunities and obstacles of ecological intensification: Biological pest control in arable cropping systems

I nonindigenous species cause major environmental damage in many different ecosystems worldwide. In a recent assessment, the costs to the US economy inflicted by invasive species were estimated at $137 billion annually (Pimentel et al. 2000). The US government therefore has expanded its efforts to combat exotic pests, as well as to accelerate research on habitat restoration and biologically based, integrated pest management tactics. Classical biological control (that is, the deliberate release of natural enemies to control exotic pests) is an important tool in integrated pest management, and it is usually considered to be economically sound and environmentally safe. However, safety of classical biological control has recently become a matter of debate concerning the risks posed by the introduced enemies to nontarget organisms and to biodiversity in general. This shift in the assessment of biological control arose mainly from recent findings of nontarget effects caused by biocontrol agents introduced through classical biological control programs (Simberloff and Stiling 1996, Louda et al. 1997, Strong 1997). The importance of the topic emerged in subsequent publications discussing such topics as benefits of biological control (Gurr and Wratten 2000), ecological relevance of nontarget attack (Follet and Duan 2000, Wajnberg et al. 2001), evolutionary stability (Jervis 1997), and the use of modeling in biological control (Thomas and Willis 1998). One of the most critical points of contention is whether and to what extent host-specificity tests of potential biocontrol agents are useful in assessing potential risks toward nontarget organisms (McEvoy 1996). Although prerelease studies in general, and host range testing in particular, only recently have begun to be part of biological control programs against insect pests, they have a long-standing tradition in the classical biological control of weeds. The report of host range expansion of the weevil Rhinocyllus conicus Froel. (Figure 1; Louda et al. 1997), introduced in North America to control exotic thistles, has therefore puzzled many environmentalists and theoretical ecologists and has contributed to a general discomfort about the effectiveness of prerelease studies. In this paper, I discuss the potential and limits of host range testing in predicting ecological and evolutionary changes in the host range of biocontrol agents after their release in a target area. Particular emphasis is placed on the usefulness of detailed behavioral and genetic studies in improving the interpretation of standard host range tests.

Globally, invasions by alien plants are rapidly increasing in extent and severity, leading to large-scale ecosystem degradation. Weed biological control offers opportunities to arrest or even reverse these trends and, although it is not always effective or appropriate as a management strategy, this practice has an excellent record of safety and many notable successes over two centuries. In recent years, growing concerns about the potential for unintended, non-target damage by biological control agents, and fears about other unpredictable effects on ecosystems, have created an increasingly demanding risk-averse regulatory environment. This development may be counter-productive because it tends to overemphasize potential problems and ignores or underestimates the benefits of weed biological control; it offers no viable alternatives; and it overlooks the inherent risks of a decision not to use biological control. The restoration of badly degraded ecosystems to a former pristine condition is not a realistic objective, but the protection of un-invaded or partial restoration of invaded ecosystems can be achieved safely, at low cost and sustainably through the informed and responsible application of biological control. This practice should therefore be given due consideration when management of invasive alien plants is being planned. This discussion paper provides a perspective on the risks and benefits of classical weed biological control, and it is aimed at assisting environmental managers in their deliberations on whether or not to use this strategy in preference, or as a supplement to other alien invasive plant control practices.

While organic farming practices, which are often promoted as models of ecological intensification, generally enhance biodiversity, their effects on the delivery of ecosystem services, such as biological pest control, are still unknown. Here, using a multi-scale hierarchical design in southwestern France, we examined the effects of organic farming and seminatural habitats at the local and landscape scales on biological control services of three pests, including weeds and insects, in 42 vineyards. Organic farming at the local and landscape scales was beneficial to the mean and temporal stability of biological control services, while the proportion of seminatural habitats in the landscape reduced the level of biological pest control potential. The effects of organic farming and seminatural habitats across spatial scales varied with the type of prey considered and with time. Egg moth removal rates were higher in fields under organic management compared to conventional management while weed seed removal rates increased with the proportion of organic farming in the landscape. Larval removal rates as well as seed removal rates were always more stable within time in organic fields than in conventional fields. Moreover, independently of farming system type, local variables describing the agricultural management intensity, such as pesticide use or crop productivity, were also found to be important variables explaining levels of biological control services. Pesticide use tended to reduce biological control potential, while crop productivity was associated with contrasting biological control responses depending on the pest type. Our study demonstrates the need to target multiple spatial scales and to consider farming practices, as well as the proportion of seminatural habitats, to design functional landscapes that optimize biological pest control services.

The potential for biological control of homopterous pests of agricultural crops in the Caribbean region is supported by a rich history of successes and some biological and ecological attributes which favor this approach to pest management. A review of the discovery and importation of parasites and predators of citrus blackfly, Aleurocanthus woglumi Ashby into Caribbean Basin countries and subsequent repeated utilization of these natural enemies in newly invaded areas provides evidence that: 1.) Success with a pest in one area is generally transferrable, particularly if cooperation can be established; 2.) More than one natural enemy species can be utilized, and several species can contribute to the ultimate success of the project; 3.) Natural enemies from different regions are sometimes effective under varying conditions in the target areas of introduction; 4.) Successful suppression of a serious pest over a broad area can be obtained with little initial investment via classical biological control; and 5.) No deleterious effects of the successful biological control effort on citrus blackfly were identified, compared to those associated with repeated use of chemical pesticides over a similar area of infestation. Other examples cited provide evidence for the continued emphasis on development and implementation of biological control of the Homoptera.

Zeugodacus cucurbitae(Coquillett) (Diptera: Tephritidae) is a serious agro‐economic pest of cucurbits around the world. Management of tephritid fruit flies is till date mainly dependent on the use of chemical pesticides. In a rising concern about environment quality and rapid development of resistance in insect pests, biological control of insect pests is being contemplated, and in response, research approaches are constantly evolving. Various naturally occurring control agents of melon fruit fly such as parasitoids, bacteria, fungi and nematodes have potential in the management ofZ. cucurbitae. Many parasitoids includingPsyttalia fletcheri,Fopius arisanus,Dirhinus giffardiiandSpalangia endiusare known to attack various life stages ofZ. cucurbitae. Although parasitoids are being principally exploited for control ofZ. cucurbitae, various other entomopathogens such as fungi (Beauveria bassiana,Paecilomyces fumosoroseus,Metarhizium anisopliae), bacteria (Bacillus thuringiensis), nematodes (Heterorhabditis indica,Steinernema feltiae) and microbial toxins/products (spinosad, avermectin) are being investigated or used for biological control. The development of farming methodologies with greater credence on ecosystem services such as biological control ofZ. cucurbitaewill increase sustainability of agroecosystems. This review provides a concise compilation of these biological control agents along with their effectiveness and will help researchers in designing various integrated pest management strategies againstZ. cucurbitaethat involve biological control agents.

Conventional agriculture in the global north is typically characterized by large monocultures, commonly managed with high levels of pesticide or fertilizer input and mechanization. Strip intercropping, that is, diversifying cropland by growing strips of different crops using conventional machinery, may be a viable strategy to promote natural predator diversity and associated biological pest control in such conventional farming systems. We tested the influence of strip intercropping of conventionally managed winter wheat with oilseed rape, using common machinery with 27–36 m broad strips, on arthropod predator diversity and biological pest control. We characterized spider and carabid beetle communities, calculated pest aphid and pollen beetle densities and recorded parasitism rates for both crops (number of mummified aphids on wheat and number of parasitized pollen beetle larvae on oilseed rape). We observed a significant reduction in the densities of wheat aphids (50% decrease) and pollen beetle larvae (20% decrease) in strip intercropping areas compared to monocultures. Parasitism rates of wheat aphids increased significantly from 10% in monocultures to 25% in strip intercropping areas. The number of parasitized pollen beetle larvae did not show the same pattern but was higher towards the centre of the oilseed rape strip. Overall, the composition of predator communities benefited from the close neighbourhood of the two crop species in the strips, as carabid beetles were more abundant in oilseed rape and spiders were more abundant in wheat fields. Overall, strip intercropping reduced the dominance of one predator group and allowed for an equal representation of both spiders and carabid beetles in the mixture. Synthesis and applications. Our study presents evidence of the benefits of adopting strip intercropping with relatively large strips (adapted to existing machinery) for natural predator diversity and biological pest control in a large‐scale conventionally managed farm scenario. Wheat–oilseed rape strip intercropping reduced pest densities, increased parasitism of wheat aphids and promoted equal representation of natural predator groups well beyond the areas of monoculture. Overall, by reducing the area dedicated to only one crop, the implementation of strip intercropping adapted to mechanized agricultural scenarios can be used to increase crop heterogeneity at regional scales and enhance biodiversity and biological control, even in simplified landscapes dominated by large‐scale conventional agriculture.

Agriculture and forestry cover more than 75% of Europe, and invertebrate pests are a costly challenge for these two economic sectors. Landscape management is increasingly promoted as a solution to enhance biological pest control, but little is known on its effects on adjacent crop fields and woodlands. This study aims to explore the effect of the proportion of woodlands and permanent grasslands as well as crop diversity on biological pest control simultaneously in cereals fields and woodland patches, in south-western France. We used different types of sentinel prey as well as bird and carabid community metrics to assess biological pest control potential in these two ecosystems. We first show that land cover variables influence biological pest control both in cereal fields and woodland patches, but have antagonistic effects in the two ecosystems. Although results vary according to the biological control indicator considered, we show that increasing landscape heterogeneity represents a valuable solution to manage trade-offs and promote higher average predation rates across forests and cereal fields. Our study therefore calls for more integrative studies to identify landscape management strategies that enable nature-based solutions across ecosystems.

Plant diseases need to be controlled to maintain the quality and abundance of food, feed, and fiber produced by growers around the world. Different approaches may be used to prevent, mitigate or control plant diseases. Beyond good agronomic and horticultural practices, growers often rely heavily on chemical fertilizers and pesticides. Such inputs to agriculture have contributed significantly to the spectacular improvements in crop productivity and quality over the past 100 years. However, the environmental pollution caused by excessive use and misuse of agrochemicals, as well as fear-mongering by some opponents of pesticides, has led to considerable changes in people’s attitudes towards the use of pesticides in agriculture. Today, there are strict regulations on chemical pesticide use, and there is political pressure to remove the most hazardous chemicals from the market. Additionally, the spread of plant diseases in natural ecosystems may preclude successful application of chemicals, because of the scale to which such applications might have to be applied. Consequently, some pest management researchers have focused their efforts on developing alternative inputs to synthetic chemicals for controlling pests and diseases. Among these alternatives are those referred to as biological controls.

Dynamical analysis, optimum control and pattern formation in the biological pest (EFSB) control model