Can cruciferous agroecosystems grown under variable conditions influence biological control ofPlutella xylostella(Lepidoptera: Plutellidae)?

Abstract

Determining the most efficacious method for the release of parasitoids is challenging, depending on the crop area to be covered and the environmental conditions created by the agroecosystem. Release of the parasitoid Oomyzus sokolowskii (Kurdjumov) and the effect of crucifers cropping systems were investigated in relation to diamondback moth (DBM), Plutella xylostella (L.) control. First, we investigated the dispersal ability of O. sokolowskii. Kale plants were infested with 20, 25, 30 and 35 DBM larvae each, at distances of 0, 8, 16, and 24 m, from a central release point in the field. Second, the effect of a multiple host plant system composed of cabbage, broccoli and Napa cabbage on the parasitism capacity of O. sokolowskii was investigated. Lastly, the parasitism capacity of O. sokolowskii and the colonization rate of DBM were investigated comparing cropping systems composed of either a monoculture of cabbage, or three different intercropping systems: cabbage and green onion, cabbage and cilantro, and cabbage, green onion and cilantro. For all experiments, selected plants were infested with sentinel DBM larvae and caged with mesh that allowed parasitoids to search inside the cages while reducing the impact of opportunists on DBM larvae. Results showed that parasitoids were able to disperse and parasitize P. xylostella at similar rates throughout a field of kale up to 24 m from the release point. Intercropping of cabbages with other crop plants did not negatively affect parasitism rates of O. sokolowskii, which makes it promising for DBM biological control; however it did not interfere with cabbage colonization by DBM.

Diamondback Moth, Plutella xylostella (L.) in Southern Africa: Research Trends, Challenges and Insights on Sustainable Management Options

“…Generally, moths do not oviposit on non-host plants; their host acceptance and oviposition is associated with a complicated integrated suite of chemical and physical cues [86]. Therefore, where soft insecticides are utilised, crop systems approached through the modification of agro-ecosystems and cropping practices can also be manipulated to confuse the adults' host finding techniques [88]. Research has Figure 5.…”

Sustainable Agriculture and Climate Change

“…Research has shown partial DBM repellence success of cabbage intercrops with alliums through confusion in the chemical cues [12,78,79]. In such intercrops, natural enemies were shown to disperse and parasitise DBM at similar rates as in monocrops [88], evidence of compatibility between natural enemies and a cropping systems approach. There is potential in further improving this concept into a 'push-pull' cropping system technology by selecting appropriate repellent and attractant crops.…”

“…Generally, moths do not oviposit on non-host plants; their host acceptance and oviposition is associated with a complicated integrated suite of chemical and physical cues [86]. Therefore, where soft insecticides are utilised, crop systems approached through the modification of agro-ecosystems and cropping practices can also be manipulated to confuse the adults' host finding techniques [88]. Research has shown partial DBM repellence success of cabbage intercrops with alliums through confusion in the chemical cues [12,78,79].…”

“…In some developing middle-income countries (e.g., Malaysia), threshold levels of pesticide residues permissible in crop products are well-laid out and monitored at different levels of the market value chain [88]. The lack of such policies in SA and the subsequent lack of regulatory frameworks account for the high pesticide residues in fresh products [2,42].…”

Peran Tumbuhan Berbunga Sebagai Media Konservasi Artropoda Musuh Alami (The Role of Flowering Plants in Conserving Arthropod Natural Enemies)

“…Penelitian mereka juga menunjukkan bahwa penanaman sawi (famili Brassicaceae) yang diseling dengan tumbuhan famili non-Brassicaceae menarik lebih banyak predator dan parasitoid yang menyebabkan jumlah kematian lebih tinggi pada larva Plutella xylostella dan Pieris rapae, hama utama tanaman Brassicaceae, dibandingkan dengan plot yang hanya ditanami sawi. Agroekosistem tanaman Brassicaceae (krusifer, kubisan) yang dibudidayakan melalui penganekaragaman jenis tanaman di sekelilingnya, ternyata mampu memperkuat usaha pengendalian hayati ulat daun kubis Plutella xylostella menggunakan parasitoid Oomipus sokolowski (Silva Torres et al, 2011). Dalam hal ini, keragaman vegetasi meningkatkan keragaman spesies musuh alami yang berpotensi menekan populasi organisme pengganggu tanaman seperti juga ditunjukkan oleh Straub dan Snyder (2008) pada pertanaman sawi dan kentang.…”