A group of scientists from the Federal Research Center for Cultivated Plants (Germany) proposes the use of ionizing radiation to combat nematodes. An article published in Agronomy 2022 on www.mdpi.com explains the new approach.
"Potato cyst nematodes Pale Globodera и G. Rostochiensis are serious pests that cause significant economic crop losses.
Infection symptoms, such as stunting and yellowing of the leaves, are rather non-specific and appear in the later stages of plant development. New populations Globodera spp.. with high virulence, overcoming all known types of resistance in potato varieties, can occur at any time.
Preventing the spread of these two types of nematodes is extremely important. Soil fragments adhering to tubers are still a source of nematode cysts.
Disinfection measures such as γ- and β-irradiation are used in the decontamination of packaging material and disposable medical products from a wide range of pathogens and pests.
In the food industry, irradiation prolongs shelf life or inhibits the germination of fungal spores. The energy density absorbed by a material is expressed in units of Gray dose (Gy), where 1 Gy is defined as the energy of 1 J transferred to a mass of 1 kg in an ionizing radiation field with a constant energy flux density.
The treated material itself does not become radioactive, since the irradiation does not contain any radioactive atoms or particles, and the irradiated material does not come into contact with the radiation source.
Lethal doses vary for different organisms; fungi and invertebrates are more sensitive to γ-irradiation, while bacteria appear to be resistant to doses up to 25 kGy.
Several studies have previously examined the effects of gamma irradiation on nematodes. The method has been shown to work well on free-living nematodes by disrupting spermatogenesis or increasing the proportion of small adult males in the population, but sensitivity to gamma irradiation varied between different nematode species, and G.rosochiensis was more susceptible than Heterodera schachtii.
In a study by German scientists, it was checked whether the viability and formation of nematode cysts were suppressed by γ- and β-irradiation.
In the first experiment, nematode cysts were treated with γ- or β-irradiation without soil matrix to determine the parameters of the minimum dose in the range from 0 to 12 kGy.
Subsequently, two representative soil samples containing cysts were irradiated. Irradiation of γ and β at doses of 0, 1, 4, 8 and 12 kGy was carried out under controlled conditions at Synergy Health Radeberg GmbH (Radeberg, Germany) by specially trained personnel.
The effect of irradiation on viability and new cyst formation was assessed using hatch tests and biological assays with susceptible potato plants, respectively. Similar tests were carried out on corn seedlings, because potatoes in Germany are usually grown in rotation with this crop.
Found that 4 kGy was the minimum dose of gamma or beta irradiation in experiments for complete inactivation G. pallida and G. Rostochiensis. The minimum yield of juvenile nematodes was found only in cysts G. rostochiensisexposed to direct exposure to β-irradiation at a dose of 4 kGy, which indicates species-specific reactions.