Predators increase whitefly control in tomato plants

The joint release of Nesidiocoris tenuis and Orius laevigatus reduced egg density by 79,50% and nymph density by 78,02% Bemisia tabaci in tomato plants grown in a greenhouse. The result surpassed the performance of predators used in isolation and increased crop productivity components, without compromising the evaluated fruit quality parameters. None of the species exist in Brazil.

The research evaluated the biological management of whitefly in tomato plants under controlled conditions in Saudi Arabia. The experiment took place at the National Organic Agriculture Center in Unaizah, Al-Qassim, between December 2024 and June 2025. The scientists worked with the Newton tomato cultivar in a 360-square-meter greenhouse. The temperature remained at 24 degrees Celsius, with a variation of one degree Celsius. The relative humidity was between 60% and 70%.

Six treatments

The researchers compared six treatments. The list included isolated release of Nesidiocoris tenuisisolated release of Orius laevigatus, joint release of the two predators, control without treatment, organic insecticide based on azadirachtin and chemical insecticide dinotefuran 20% SG. The plots received adults of Bemisia tabaci In early February 2025, at a dose of 20 adults per plot. The predator releases occurred on March 18 and April 20, 2025.

In isolated treatment, Nesidiocoris tenuis It had the greatest effect on eggs. The average reduction reached 67,44%. Orius laevigatus The reduction in egg production was 57,71%. When the two predators acted together, the reduction increased to 79,50%. The difference between treatments was statistically significant.

For nymphs, Orius laevigatus It showed slightly better performance when used in isolation. The average reduction reached 63,30%. Nesidiocoris tenuis The combined release reduced nymph populations by 60,73%. The combined release reached 78,02%. Scientists interpreted the result as a possible additive or synergistic effect between the predators.

chemical treatment

The chemical treatment showed the greatest reductions among all treatments. It reduced eggs by 88,81% and nymphs by 85,74%. The combination of predators outperformed the isolated biological treatments and the organic insecticide. The organic insecticide reduced eggs by 50,47% and nymphs by 52,88%.

The pest population grew throughout the evaluation period in the untreated plots. Egg density ranged from 3,44 to 32,24 eggs per leaf. The highest egg density occurred in the eleventh weekly evaluation. Nymph density ranged from 4,48 to 124 individuals per leaf. The peak nymph population occurred in the fifteenth evaluation.

Fruit quality

In terms of fruit quality, the combined treatment stood out for its vitamin C content, reaching 124,66 milligrams per 100 grams. This value surpassed the other treatments and showed a statistically significant difference. The same treatment recorded 2,42% nitrogen and 13,97% protein. The differences in phosphorus, potassium, total phenols, and total soluble solids did not show statistical significance.

Scientists stated that the predators act in a complementary way on different stages of the pest. Nesidiocoris tenuis It had a greater effect on eggs. Orius laevigatus had a greater relative effect on nymphs. This complementarity favored greater suppression of Bemisia tabaci and improved tomato plant productivity in greenhouses.

Further information at doi.org/10.3390/insects17060582