By Blake Jackson
Penn State researchers have discovered that increased soil salinity can offer a surprising benefit to tomato plants: reduced damage from the destructive tomato fruitworm.
The study revealed that higher salt content in tomato plants deters fruitworm larvae feeding and decreases the number of eggs laid by moths. However, this saltiness comes with a trade-off, as it can also stress and stunt the plants.
“The top global tomato producers like in India, Florida, California and some Mediterranean and African countries have warm and arid climates with improper irrigation, which causes accumulation of salts in the soil,” said Lead author Sahil Pawar. “Many poorer countries also resort to irrigating crops with whatever water is available to them, and this causes further increases in soil salinity. All in all, if we want to ensure tomato yields are maintained in these environments, we should be studying the impacts of salinity on plant traits.”
Interestingly, salty plants experienced less insect feeding when herbivores had a choice, and moths preferred to lay eggs on unsalted plants. Pawar was surprised that the plants' defense proteins weren't more active under salty conditions.
Further investigation showed that high salt concentrations in artificial diets were toxic to fruitworm larvae, hindering their survival, growth, and even the reproductive capabilities of surviving moths.
The study also indicated that increased salt altered the plants' scent profile, making them less attractive to egg-laying moths. Pawar stated this is "great for farmers, as a drop in the number of tomato fruitworm eggs means fewer larvae available to eat their crops in the future."
While acknowledging the potential for reduced yield with high salt levels, Pawar suggests the possibility of an "ideal amount of salt pressure" that could deter pests without compromising production. Pawar even proposed that this optimal salinity might enhance tomato flavor.
Pawar added, "There are other studies out there about how increased salinity makes smaller fruits and lowers water content, and thus it enhances tomato fruit taste by increasing both sugars and acids" Further research could explore the precise application of low salt levels in agriculture to achieve this balance.
Photo Credit: gettyimages-bastetamn
Categories: Pennsylvania, Crops, Fruits and Vegetables, Education