The western leaffooted bug, Leptoglossus zonatus (Dallas) (Heteroptera: Coreidae), is a key pest of almonds and pistachios in the USA. With limited monitoring strategies and no economic threshold developed, the use of broad-spectrum insecticides remains the primary control tactic for L. zonatus. In pursuit of more sustainable management options, experiments were carried out to assess the biocontrol potential of the egg parasitoid Hadronotus pennsylvanicus (Ashmead) (Hymenoptera: Scelionidae) against L. zonatus. Biological and demographical attributes of H. pennsylvanicus were evaluated under controlled laboratory conditions. Mated females lived on average 116 days. However, female longevity declined by 74% when provided with host eggs, and by 97% when deprived of a suitable diet. Females produced an average 39.70 offspring, with peak fecundity observed within the first week of their lifespan. The total progeny was on average 92.75% female. Non-reproductive host mortality accounted for > 52% of the total egg mortality observed within the first two weeks, and represented the majority of total host egg mortality thereafter. Age of host eggs did not influence parasitism rates. Under laboratory conditions, H. pennsylvanicus exhibits suitable demographic and reproductive traits as a candidate biocontrol agent of L. zonatus. Further research is needed to determine how to best manipulate and enhance H. pennsylvanicus populations to promote biocontrol of L. zonatus under field conditions.

Cocoa yields in Ghana remain low. This has variously been attributed to low rates of fertilizer application, pollinator limitation, and particularly dry growing conditions. In this paper we use an African forest-agriculture landscape dominated by cocoa (Theobroma cacao) to develop an ecological production function, allowing us to identify key ecological and management limits acting on cocoa yields simultaneously. These included more consistent application of fertilizers inter-annually, distributing rotting biomass throughout the farm and reducing the incidence of capsid attacks. By relaxing these limits, we estimate plausible increases in yields and, by extension, farm incomes. Our analysis reveals that resulting increases in cocoa yields requiring both ecological and intensive management interventions could be significant (113 ± 60%); however, benefits are disproportionately realized by the wealthiest households. We found that wealthier households benefited proportionally more from ecological intensification methods (e.g., leaving more rotting biomass in their farms) and the poorest households benefited proportionally more from capital-intensive intensification methods (e.g., pesticide and fertilizer applications). We treated poverty as multi-dimensional, and show that only certain dimensions of poverty (school attendance, assets, and food security) are significantly related to cocoa incomes, while several other dimensions (access to clean water, sanitation and electricity, and infant mortality) are not. We explore how increased household cocoa incomes could impact different dimensions of poverty. Our findings suggest, that if all households adopted the optimal level of each of these management options, and in so doing had similar poverty profiles to those households already managing optimally, we would see the community-averaged probability: a child of a household misses school decrease from 47 to 31%, a household would be able to acquire assets increase from 40 to 59% and a household would have access to an adequate amount of food increase from 62 to 79%.

The olive fruit fly, Bactrocera oleae, has been a key pest of olives in Europe and North America. We conducted the largest exploration for parasitoids associated with the fly across Sub-Saharan Africa (Kenya, Namibia, and South Africa) including some of the fly’s adjoining regions (Canary Islands, Morocco, Réunion Island and Tunisia). From Sub-Saharan regions, four braconids were collected: Bracon celer, Psytallia humilis, P. lounsburyi, and Utetes africanus. Results showed that their regional dominance was related to climate niches, with P. humilis dominant in hot semi-arid areas of Namibia, P. lounsburyi dominant in more tropical areas of Kenya, and U. africanus prevalent in Mediterranean climates of South Africa. Psytallia concolor was found in the Canary Islands, Morocco and Tunisian, and the Afrotropical braconid Diachasmimorpha sp. near fullawayi on Réunion Island. Furthermore, we monitored the seasonal dynamics of the fly and parasitoids in Cape Province of South Africa. Results showed that fruit maturity, seasonal variations in climates and interspecific interactions shape the local parasitoid diversity that contribute to the low fly populations. The results are discussed with regard to ecological adaptations of closely associated parasitoids, and how their adaptations impact biocontrol.

Using sown groundcovers as trap crops to protect a cash crop is a traditional pest management tool. Pistachio is a major crop in California’s Central Valley, where high summer temperatures and little to no precipitation between May and November lead to summer dry-down of annual groundcover. Hemipteran pests that consist of ‘small bugs’ and ‘large bugs’ are a major contributor to nut damage, especially in organic production. In this 2-year field study, we tested the use of irrigated trap crop mixtures, sown between tree rows, to reduce those hemipteran pests’ abundance or damage. Biweekly beat samples of the tree canopy and sweep samples of the sown groundcovers in trap crop plots and resident weedy vegetation in control plots were taken over two consecutive growing seasons. Arthropod richness and abundance were highest in the groundcover and tree canopy in the trap crop plots. Small and large bug pest populations were higher and lower, respectively, in the tree canopy in trap crop plots, indicating a mixed response of these hemipterans to the presence of the trap crops. Additionally, natural enemy populations were more abundant in the tree canopy in trap crop plots than in control plots. There was no difference in nut damage between plots with and without the trap crop. These findings suggest that populations of hemipteran pests and beneficials can be manipulated successfully with irrigated trap crops, but future studies will need to focus on doing so in a way that decreases hemipteran pistachio damage.