Drought creates increasing challenges for agriculture. As well as affecting crop growth, it also affects interactions with pests. A research team at the University of Göttingen investigated how different levels of drought affect sugar beet's susceptibility to damage caused by the beet leaf miner (Pegomya cunicularia)—a fly whose larvae create visible tunnels inside leaves.
The study shows that moderate drought promotes larval development, while severe drought adversely affects both plants and pests. The findings were published in the Journal of Experimental Botany.
Stress level changed the outcome
The researchers exposed sugar beet plants to either moderate or severe drought. They combined these conditions with an infestation by the beet leaf miner. They then analyzed various indicators of plant performance, as well as insect development and egg-laying behavior.
The outcome depended largely on the severity of the stress: In general, drought reduced sugar beet growth, leaf area and the rate of photosynthesis. Under moderate drought, however, the concentration of certain nutrients in the leaves increased.
This meant the larvae grew particularly well and caused more severe damage to the plant. Under severe drought, however, the plants' water content and physiological performance decreased significantly, considerably restricting larval development.
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A sugar beet leaf showing the visible tunnels and damaged patches caused by beet leaf miner larvae as they burrow through the leaf to feed. Credit: Shahinoor Rahman -
Dr. Shahinoor Rahman collecting plant volatiles. Credit: Musrat Zahan Surovy
Drought also changed host signals
The plant's chemical communication was also affected. "We observed that drought stress alters both the composition and abundance of plant-emitted volatile compounds, which the beet leaf miner uses to locate suitable host plants for its larvae," explains Dr. Shahinoor Rahman, who carried out the study as part of his Ph.D. research at Göttingen University's Department for Crop Sciences.
"In addition, females laid fewer eggs on plants experiencing severe stress," Rahman adds. These findings provide new insights into how climate-related changes shape crop-pest interactions and may help inform future strategies for more resilient farming systems.
Publication details
Shahinoor Rahman et al, Metabolic trade-offs in sugar beet under drought and beet leaf miner infestation: implications for herbivore success, Journal of Experimental Botany (2026). DOI: 10.1093/jxb/erag196
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Citation: Interaction between sugar beet and its pest varies depending on drought stress, researchers find (2026, July 29) retrieved 30 July 2026 from https://phys.org/news/2026-07-interaction-sugar-beet-pest-varies.html
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