Interactions between integrated pest management, pollinator introduction, and landscape context on avocado Persea americana productivity

Abstract

Pest management and insect pollination are important services that support crop production but are most often studied in isolation in cropping systems. Avocado Persea americana Mill. is an economically important crop in East Africa, which suffers from pest threats and potential drawbacks of the global pollinator crisis. The integration of pest and pollinator management is a growing research trend as a potential solution for sustainable crop production with minimum adverse effects on the environment and biodiversity. This study assessed potential interactions between landscape context, honeybee Apis mellifera L. introduction and integrated pest management (IPM) on avocado pests Bactrocera dorsalis (Hendel) and Thaumatotibia leucotreta (Meyrick), pollinators, and productivity in Kenya. Results showed an interaction between honeybee introduction and IPM on A. mellifera, with the highest mean abundance on the farms with both honeybee colonies and IPM. The abundance and diversity of non-Apis flower visitors were not affected by IPM and honeybee introduction across the landscapes. Pollinator introduction and IPM implementation resulted in a 941% fruit set increase and up to 97% fruit abscission within the high vegetation productivity class. Pest abundance significantly decreased on the farms with IPM, resulting in a 6% increase of final fruit weight compared with the farms without IPM. Overall, integration of pest and pollinator management did not synergistically increase the final avocado yield but represented a potential strategy to reduce pest densities while preserving wild visitors and benefiting from secondary products of honeybee colonies.

Interactions between integrated pest management, pollinator supplementation, and normalized difference vegetation index in pumpkin, Cucurbita maxima (Cucurbitales: Cucurbitaceae), production

“…In the first season, there was no effect of the treatments on the daily catches of Z. cucurbitae , while in the second season, Z. cucurbitae catches were higher in farms with no PS than in farms with PS, implying that the presence of stingless bee colonies did not increase the abundance of Z. cucurbitae . Contrary to our study, Toukem et al (2022) reported an increase in B. dorsalis catches on avocado farms with honeybee colonies, which was attributed to the smell of honey sugar and fermentation of beebread, which attracted fruit flies (Lee et al 2015). Furthermore, in the second season, Z. cucurbitae catches were highest in control farms across low NDVI, presumably due to fewer natural enemies (Copeland et al 2006) and as reported by Mwatawala et al (2006) for Tanzanian lowland regions.…”

“…We found the lowest daily catches of Z. cucurbitae in IPPM farms in medium NDVI, but only during the second season, illustrating a synergistic effect. Unlike in our study, Toukem et al (2022) reported no synergistic effect of IPM and PS in reduction of Tephritid fruit fly densities in avocado production systems, however, independently, IPM reduced fruit fly pest abundance. Findings from our study reported a main effect of NDVI on the catches of D. bivittatus , with the highest catches observed across low NDVI.…”

“…During the first season, the number of fruits per plant was not different across treatments, whereas in the second season, the number of fruits per plant was higher in farm plots with IPM than those without, illustrating the effectiveness of the IPM package to combat Tephritid fruit flies in cucurbits, as illustrated by Githiomi et al (2019) and Midingoyi et al (2019) for mango, Pecenka et al (2021) for watermelon, and Toukem et al (2022) for avocado. However, a higher number of fruits/plant reported in IPM farms in the second season did not translate to higher yields across the treatments.…”

“…Although spinosad-based protein baits used in the study are widely incorporated in IPM programs as a replacement for organophosphates for the control of fruit flies, they have been reported to have toxic effects on Africanized honeybees and stingless bees such as Plebeia lucii Moore (Apidae: Meliponini) (Lopes et al 2018, Marques et al 2020). However, a recent study by Toukem et al (2022) in avocado production systems in Kenya reported contradictory results, with abundant honeybee populations documented in IPM farms incorporating spinosad-based protein baits. Additionally, Koech et al (2023) reported low spinosad contamination on pollen collected by honeybees in avocado farms across Muranga landscapes.…”

“…The abundance of natural enemies particularly may in turn influence pest population in the ecosystem (Copeland et al 2006). Studies have reported how NDVI can predict the distribution and abundance of insect pests and pollinators and monitor long-term landscape structure (Abdel-Rahman et al 2017, Toukem et al 2020, 2022). For example, Toukem et al (2020) reported a high density of Tephritid fruit flies infesting avocado, Persea americana Miller (Laurales: Lauraceae), in low NDVI.…”