تعیین پراکنش نماتد Heterodera schachtii در مزارع چغندرقند استان آذربایجان‌غربی

Sugar beet is one of the most important industrial agricultural products in West Azerbaijan province. Various pathogenic agents including fungi, bacteria, viruses and nematodes, along with various pests, cause damage to this product. Sugar beet cyst nematode (Heterodera schachtii) is one of the most damaging factors in sugar beet fields of the province. Determining the areas infected with this nematode can be a very important step in its management. In order to determine the distribution areas of this nematode, 343 soil samples were collected from sugar beet fields which have contracts with sugar factories in West Azerbaijan Province in 2024. Cysts were extracted using Fenwick and population including cyst and egg was counted in 100 grams infected samples. Morphological and morphometric characteristics of cysts, cone top and J2s were surveyed. The results showed that the highest spread of pollution with the amount of 47% of the samples is related to Khoi County and the lowest spread with the amount of 11% is related to Piranshahr county. Also, in the cities of Urmia 21%, Chaipareh 19%, Seru 29%, Salmas 22%, Qareziaedin 16%, Lajan 27% and Noshinshahr 34% of the fields were infected with sugar beet cyst nematode. In average of J2s and eggs, Khoi city had the highest compared to other cities, so that the average of J2s and eggs in this city is 342.22 in all fields and 334.41 in contaminated fields. Among the various investigated fields, 7 fields had contamination between 500-1000 eggs and J2s, and these fields include 2.4% of the contaminated fields in the province. The spread of nematodes did not show any noticeable change compared to the same period last year. In addition to Heterodera schachtii, H. trifolii and H. filipjevi were also detected in some fields. Management of sugar beet cyst nematode is in challenging because the eggs will be able to survive passively inside the cysts for several years. On the other hand, due to the large displacements that are carried out in the province, it is necessary to take necessary precautions and especially not to return the contaminated soil to the fields. Considering the severity of contamination in some fields of the province, it is suggested to conduct research on controlling this nematode and identifying local and commercial varieties of sugar beet that are resistant or tolerant to it, suitable for the conditions of the cultivated fields.