Distribution of a model biocontrol agent (Serenade® MAX) in apple and pear by mason bees and bumble bees

Abstract

1 Biocontrol agents (BCAs) are commonly sprayed on flowering pipfruit trees to prevent them from getting infected by various pathogens. By entomovectoring, BCAs can be directly delivered onto the flowers. However, we currently lack knowledge on the distribution dynamics of BCAs by pollinators. 2 Here, managed bees, both bumble bees (Bombus terrestris) and mason bees (Osmia bicornis and Osmia cornuta), were placed in the vicinity of flowering pipfruit trees (pear -'Conference', and apple-'Svatava' and 'Jonagold'), and this allowed us to investigate the distribution of a model BCA, namely, Serenade® MAX, from spray-inoculated flowers of a centralized tree to non-inoculated flowers of surrounding receiver trees by bees in an experimental setup in outdoor conditions. 3 One hour after inoculation, we detected an enrichment of BCA in the flowers of the receiver trees and this for each tested pipfruit. 4 The distribution of BCA from treated to untreated flowers was homogenous between the receiver trees for 'Svatava', while significantly different loads were detected for both 'Conference' and 'Jonagold', which might be due to differences in environmental factors, and/or bee characteristics. 5 More research is needed to understand the distribution dynamics of BCAs by pollinators in field conditions, such as in commercial orchards or crop fields, and how this could result in an efficient control.

Biopesticides and insect pollinators: Detrimental effects, outdated guidelines, and future directions

“…Because of the alleged safety towards non-target insect species, especially managed pollinators, honey bees, bumblebees, and mason bees have also been used as direct vectors to deliver biological control agents (BCA) against crop pests (Al Mazra'awi et al, 2006;Menzler-Hokkanen and Hokkanen, 2017;Maebe et al, 2021). The use of pollinating insects to spread BCA has its origin in the early '90s and in the last 15 years "pollinator-and-vector technology" has been systematically developed to improve sustenaibility, yield and quality in organic crop production (Smagghe et al, 2020).…”

Current Knowledge About Microorganisms Used in Biological Control of Pests and Their Relation to Bees: A Review

“…Honey bee (or also bumble bee) hives can be fitted with special dispensers of biological control agents (bacteria, fungi, viruses) that are antagonistic to microbial pathogens and pest insects (Kevan et al, 2003). Maebe et al (2021) Shimanuki and Knox (2000) indicated the wax month (Galleria mellonella Linnaeus c , Achroia grisella Fabricius c , Ephestia kuehniella Zeller c ), small hive beetle (Aethina tumida Murray c ) and the beelouse (Braula coeca Nitzsch c ) as the honey bee pests. Abou-Shaara and Staroň (2019) also included Varroa destructor Anderson and Trueman c mites (Figure 1), Vespa Linnaeus c hornets and parasitic flies into the group of honey bee pests.…”