Phytophagous insects and natural enemies in kale under organic and chemical fertilizers

ABSTRACT: Organic agriculture is distinguished by practices that benefit the environment and support sustainable agriculture. In the present study, leafy kale, Brassica oleracea L. var. acephala DC., was submitted to chemical and organic (castor bean cake and bovine manure) fertilization treatments aiming to verify the influence of these fertilizers on the occurrence of insect pests and natural enemies. The insects were sampled by visual examination of plants and pitfall traps. Brevicoryne brassicae (L.) and Myzus persicae (Sulzer) (Hemiptera: Aphididae) were the phytophagous insects that occurred more significantly in kale, under chemical rather than organic fertilization, whereas Harmonia axyridis (Pallas), Hippodamia convergens (Guérin-Méneville) (Coleoptera: Coccinellidae), Diaeretiella rapae (M’Intosh) (Hymenoptera: Braconidae) and spiders (Arachnida: Araneae) were abundant in kale under organic fertilizer. The study showed that castor bean cake and bovine manure as leafy kale fertilizers can reduce the use of insecticides and provide quality food.

摘要：有机农业以有益于生态环境、支撑可持续农业发展的生产实践为核心特征。本研究以羽衣甘蓝（Brassica oleracea L. var. acephala DC.）为试验材料，设置化学施肥与有机施肥（蓖麻饼肥、牛粪肥）两种处理方案，旨在探究两类施肥方式对害虫与天敌昆虫发生动态的影响。昆虫样本采集采用植株目视调查与陷阱诱捕法。研究发现，甘蓝蚜（Brevicoryne brassicae (L.)）与桃蚜（Myzus persicae (Sulzer)）（半翅目：蚜科）为羽衣甘蓝上的优势植食性昆虫，在化学施肥处理下其种群发生量显著更高；而异色瓢虫（Harmonia axyridis (Pallas)）、汇聚瓢虫（Hippodamia convergens (Guérin-Méneville)）（鞘翅目：瓢虫科）、菜蚜茧蜂（Diaeretiella rapae (M’Intosh)）（膜翅目：茧蜂科）以及蜘蛛（蛛形纲：蜘蛛目），在有机施肥处理的羽衣甘蓝上种群更为丰富。本研究结果表明，以蓖麻饼肥与牛粪肥作为羽衣甘蓝的有机肥源，可减少杀虫剂的使用量，同时产出优质食用农产品。