In the heart of China’s Guizhou Province, researchers have made a breakthrough that could revolutionize pest control in soybean fields worldwide. Ji-Zhi Xue, a scientist at Guizhou University’s State Key Laboratory of Green Pesticides, has been working on a novel approach to combat the soybean pod borer (SPB), a pest that has long plagued soybean farmers. The results of his team’s work were recently published in the journal *Biological Control*, which translates to “生物防治” in Chinese.
The soybean pod borer is a notorious pest that can cause significant damage to soybean crops. Traditional methods of control have often relied on chemical pesticides, which can be harmful to the environment and human health. In recent years, there has been a growing interest in biological control methods, which involve using natural enemies of the pest to control its population.
One such natural enemy is the egg parasitoid *Trichogramma leucaniae*, a tiny wasp that lays its eggs inside the eggs of the soybean pod borer, ultimately killing the pest before it can cause damage. However, mass-rearing this parasitoid has been a challenge, as it has typically been done using Chinese oak silkworm eggs, which can be inconsistent and lead to declining parasitism rates over generations.
Xue and his team have found a solution to this problem in an unlikely place: the eri silkworm (*Samia ricini*). “We were looking for a more reliable and sustainable host for mass-rearing *Trichogramma leucaniae*,” Xue explains. “We turned our attention to the eri silkworm, which is widely available and easy to rear.”
The results of their study were impressive. Over ten generations, the team found that the parasitism and emergence rates of *Trichogramma leucaniae* reared on eri silkworm eggs increased significantly, from 43.33% and 46.7% in the first generation to 90.0% and 86.7% in the tenth generation, respectively. The rearing system also achieved stability in critical biological parameters, such as pre-emergence time, adult emergence per egg, and sex ratio, with female proportions exceeding 90.0% after the fifth generation.
Comparative analyses showed that *Trichogramma leucaniae* reared on eri silkworm eggs performed just as well as those reared on Chinese oak silkworm eggs and significantly outperformed those reared on rice moth eggs in parasitizing soybean pod borer eggs across various developmental stages.
The implications of this research are significant for the agricultural industry, particularly for soybean farmers. “This study establishes eri silkworm eggs as a superior factitious host for the sustainable mass production of *Trichogramma leucaniae*,” Xue says. “Our findings offer a practical solution to enhance biological control strategies of the soybean pod borer in soybean agroecosystems, contributing to the broader goal of sustainable pest management in short-lasting cropping systems.”
The use of eri silkworm eggs as a host for mass-rearing *Trichogramma leucaniae* could have a significant impact on the agricultural industry. It could lead to more reliable and sustainable biological control methods, reducing the need for chemical pesticides and ultimately benefiting the environment and human health.
As the world grapples with the challenges of climate change and sustainable agriculture, this research offers a glimmer of hope. It is a testament to the power of scientific innovation in addressing real-world problems and shaping a more sustainable future. The findings of this study could pave the way for future developments in the field of biological control, offering new possibilities for sustainable pest management in a variety of cropping systems.