浙江省中部某苗木产业园区移栽苗木泥球携带钉螺输出的风险评估

Risk Assessment of Snail Output Via the Mud Balls of Transplanted Seedlings in a Nursery Stock Park in Middle Region of Zhejiang Province

目的调查浙江省中部某苗木产业园区钉螺分布情况,评估移栽苗木泥球携带钉螺输出的风险,为制定相关防治措施提供依据。方法2014-2016年选择浙江省中部有螺地区某苗木产业园区的3种苗木[分别是桂花树(大乔木)、茶梅树(小乔木)、小叶冬青树(灌木)]种植区调查有螺面积和活螺密度;随机抽取桂花树、茶梅树、小叶冬青树苗木各30株,调查各苗木植株地径区域内(以苗株为中心,桂花树查螺半径为100 cm;茶梅树和小叶冬青树苗株查螺半径为30 cm)的钉螺分布情况,以及土壤各分层(表层、浅层0~3 cm、深层3 cm^10 cm)中的钉螺分布情况。另随机选取钉螺密度较高的红叶石楠树(小乔木)苗木区的移栽苗木50株,调查随移苗木泥球中钉螺的携带情况,评估移栽苗木的钉螺输出风险。结果调查结果显示,浙江省中部某苗木产业园区桂花树(大乔木)、茶梅树(小乔木)和小叶冬青树(灌木)3种苗木种植区的面积分别有3 930、2 000和1 700 m^2,有螺面积分别为200、900和800 m^2,活螺密度分别为0.08、0.56和0.55只/0.1 m^2。3种苗木土壤分层调查结果显示,桂花树、茶梅树、小叶冬青树植株地径区域内共检获钉螺分别为238、654和645只,其中土表层检获钉螺分别为159、461和376只,分别占各种苗木总螺数的66.8%、70.5%和58.3%,均高于各种苗木浅土层和深土层所占的比例(P<0.01)。50株红叶石楠树移栽苗木泥球中均携带有钉螺(检出率为100%),共检获钉螺3 726只,平均75只/株,其中成螺706只(占19.0%),幼螺3 020只(占81.0%)。结论浙江省中部某苗木产业园区钉螺密度较高,主要分布在土表层,移栽苗木泥球中有携带钉螺现象,存在苗木移栽输出钉螺的风险。

Objective To investigate the distribution of snails in a nursery stock park in the middle region of Zhejiang Province and assess the risk of snail output via the mud balls of transplanted seedlings, to provide scientific data for making strategies for snail control. Methods We selected three species of seedlings including Osmanthus fragrans（a large tree）, Camellia sasanqua（a small tree）, and Purpus privet（a type of shrub） in a nursery stock park in a snail-positive middle region of Zhejiang Province during 2014-2016 to calculate the areas of regions with snails and the density of living snails. In 30 trees of each species, the distribution of snails within the seedlings ground diameter（radius of investigation, 100 cm for Osmanthus fragrans; 30 cm for Camellia Sasanqua and Purpus Privet） and in different soil layers（surface and superficial layers, 0-3 cm; deep layer, 3-10 cm） was assessed. In addition, the presence of snails in mud balls of 50 trees of Photinia fraseri（a small tree with high density of snails） was investigated to assess the risk of snail output. Results In the planting areas of Osmanthus fragrans（3 930 m2）, Camellia sasanqua（2 000 m2）, and Purpus privet （1 700 m2）, the areas of snail-positive regions were 200, 900 and 800 m2, respectively, with the density of living snails being 0.08, 0.56 and 0.55/0.1 m2. For Osmanthus fragrans, Camellia sasanqua and Purpus privet, 238, 654 and 645 snails were detected respectively within their seedlings ground diameter, including 159（66.8%）, 461（70.5%） and 376 （58.3%） snails in the surface layer, respectively, which were significantly higher than those in the superficial and deep layers（P〈0.01）. Snails were found in all the 50 trees of Photinia fraseri（3 726 snails, 706 adult snails and 3 020 immature snails, 75 snails/tree on average）. Conclusion There is a high density of snails in the nursery stock park in the middle region of Zhejiang Province. The snails are distributed mainly in the surface layer, suggesting a risk of snail output through mud balls.