Sustainable aphid control is one of the major priorities for pest scientists — and researchers from China may have found a novel solution in the form of a widely-used food additive.
The team from Qingdao Agricultural University tested whether lactisole, a compound which suppresses sweet tastes in foods such as jellies and jams, might influence aphid feeding, with the approach showing some positive results.
In their laboratory studies, they found that both the both the green peach aphid (Myzus persicae) and the English grain aphid (Sitobion avenae) avoided settling on both an artificial diet containing lactisole and cabbage and wheat plants which had their roots drenched with the compound in solution.
The weights of both species reduced when feeding on the lactisole diet or on plants which had received the root drench, while the aphids fed the experimental diet also produced fewer offspring.
Fighting sugar perception
“Phloem-feeding insects, such as whiteflies, planthoppers, and aphids, primarily rely on sucrose to locate their feeding sites, that is, the phloem of their host plants. This inspires us to develop strategies aimed at disrupting sugar perception processes to control phloem-feeding insects,” the scientists wrote in Journal of Economic Entomology.
They noted that sugar receptor genes have been identified in such insects, which can pose problems for farmers when appearing in large numbers on crops.
The success of the experimental approach is likely to be down to lactisole bonding to the insects’ sweet taste receptors, they said, stopping them being able to detect their desired sugars. The study also showed that S. avenae probed wheat plants treated with lactisole more than controls, but spent less time feeding on them.
Their novel technique could “provide a new direction for aphid control,” they said, but noted that “further experiments are required to determine the distribution of lactisole within plants and the duration of its aphid-resistant effect.”
Overcoming plant growth pitfall
While the use of lactisole has promise in deterring aphids from economically important crops, a major caveat as it stands is that when it was applied as a root drench, it had a significant negative effect on plant growth.
“Future research should enhance the efficacy of sweet taste inhibitors on insects while mitigating their adverse effects on plant growth, possibly through the synthesis of lactisole derivatives or the development of novel sweet taste inhibitors,” they added.
