Insect netting: effect of mesh size and shape on exclusion of some fruit pests and natural enemies under laboratory and orchard conditions

Abstract To improve exclusion systems for fruit trees, insect nets of various types were evaluated their permeability to different beneficial and pest species, under laboratory field conditions. Pests studied the apple maggot, Rhagoletis pomonella (Diptera: Tephritidae) spotted wing drosophila, Drosophila suzukii Drosophilidae). Beneficials Aphidoletes aphidimyza Cecidomyiidae), Aphidius matricariae (Hymenoptera: Braconidae) Aphelinus abdominalis Aphelinidae). Mesh with five apertures (square, rectangle, triangle, rhombus hexagon) six sizes (from 0.4 2.8 mm) 3D-printed from strands polylactic acid tested in along two commercially available made polyethylene. The physical behavioral characteristics species affected ability cross nets. For an equal size (open area), intrusion rate was generally greater through square- and/or hexagonal-shaped meshes. Rectangular-shaped totally excluded maggot both trials, provided shortest side did not exceed 1.9 mm. a maximum 1.0 mm similarly required laboratory. shape factor (length/width ratio) appeared affect net selectivity. Field trials confirmed that more aphid predators leafroller parasitoids colonized trees covered larger mesh (2.3 × 3.4 mm), while still excluding maggot. Thus, similar aperture (area), elongated rectangular-shaped appears facilitate access beneficials, continuing provide effective protection against pests.