Adhesive droplets made from plant-derived oils for control of western flower thrips

Arthropod pests cause significant problems in agricultural crops all around the world. As chemical pesticide use becomes less desired, there is a need for alternative methods of pest control. Inspired by the natural adhesiveness of arthropod trapping plants, we examined the effectiveness of adhesive droplets made from oxidised and cross-linked plant-derived oils for control of western flower thrips. Two filter paper droplet adhesiveness assays and three detached chrysanthemum leaf assays were carried out to test efficacy against thrips. Suspensions containing adhesive droplets and other constituents were applied to filter papers and leaves via spraying or dipping. On filter papers, droplets made from oxidised rice germ oil (RGO) of different sizes caught 40–93% of thrips. Droplets made of a mixture of sunflower, olive, and linseed oil (MIX) caught up to 94% of thrips. Likewise, adhesive droplet-treated filter papers showed higher thrips mortality than untreated or control solution-treated filter papers. On chrysanthemum leaves, thrips were caught by both RGO (up to 40%) and MIX droplets (up to 20%) and thrips damage and reproduction were reduced. On MIX-treated leaves, thrips mortality was also increased. Within treatments, droplets of different size classes occurred and larger droplets were more effective at catching thrips in general. Droplets were also robust to rinsing with water, which is of importance for their application in horticulture. In conclusion, adhesive droplets made from edible plant oils show potential for use in control of western flower thrips.

Methods
Data type: experimental data, various measurements of Insect-bioassays performed in Petri-dishes.

Aim: to assess if adhesive droplets made from natural materials could trap thrips (tiny insects and a major pest)

Methodolgy:

Exp1: filter papers were sprayed with different sizes (R180, R360, R720) adhesive droplets made from oxidized rice germ oil. Thrips were added and at several timepoints the number of thrips stuck in the droplets was counted.

Exp2: Same as experiment 1, but with 2 different droplet prototypes (Mix, made from a mixture of vegetable oils) (RGO360-90, same as RGO360, but temperature used during oxidation set at 90C)

Exp3: same as experiment 1, but using detached chrysanthemum leaves that are placed in agar. only a single measurement after 5 days. damage to the leaf by thrips feeding was also measured, as well as reproduction of the thrips.

Exp4: same type of detached leaf assay as Exp3, but using the samples Mix and RGO360-90), this time particle coverage was also measured. application of droplets via dipping.

Exp5, same as Exp4, but this time droplets were sprayed on the leaf.

Excel files with experimental data were obtained by manual labor.

For details on the methods see the associated publication: https://doi.org/10.1007/s10340-024-01755-4