Strip-intercropping canola with annual alfalfa improves biological control of Plutella xylostella (L.) and crop yield

2017 ◽  
Vol 37 (03) ◽  
pp. 208-216 ◽  
Author(s):  
Pejman Tajmiri ◽  
Seyed Ali Asghar Fathi ◽  
Ali Golizadeh ◽  
Gadir Nouri-Ganbalani

AbstractThe population density of the diamondback moth (DBM),Plutella xylostella(L.), the species diversity of its predators, parasitism on eggs, larvae and pupae, and associated yield of canola were evaluated in experimental plots where spring canola was grown either as a monoculture or strip-intercropped with annual alfalfa in the ratio of 3C:3A, 6C:3A and 9C:3A over a 2-year period. The egg density was significantly higher in monoculture than in intercrops. The highest and lowest densities of larvae and pupae of DBM were recorded in monoculture (2.9–3.2 larvae per plant and 1.14–1.20 pupae per plant) and intercrop 3C:3A (0.7–0.6 larvae per plant and 0.34–0.29 pupae per plant), respectively. Shannon diversity index (H') for species composition of the predators of DBM immature stages was lower in monoculture than in intercrops, and was similar amongst the three intercrops. Moreover, the percent parasitism for eggs, larvae and pupae was higher in intercrops than in monoculture. The dry seed weight loss was higher in monocrop (37.6–40.1%) compared to 3C:3A (7.9–8.6%), 6C:3A (19.5–21.4%) and 9C:3A (21.6–25.4%). Our results indicate that intercropping canola with annual alfalfa, especially in the ratio 3C:3A, can increase the species diversity, parasitism rates of DBM immature stages, and enhance the yield of canola. The implications of these findings, in relation to integrated pest management (IPM) in canola cropping systems, are discussed.

2000 ◽  
Vol 90 (3) ◽  
pp. 221-231 ◽  
Author(s):  
Shu-Sheng Liu ◽  
Xin-Geng Wang ◽  
Shi-Jian Guo ◽  
Jun-Hua He ◽  
Zu-Hua Shi

AbstractAn investigation of insect parasitoids of the diamondback moth, Plutella xylostella(Linnaeus), in brassica vegetable crops in the suburbs of Hangzhou was conducted during five periods from 1989 to 1997. Eight species of primary parasitoids were recorded: Trichogramma chilonis Ishii, Cotesia plutellae Kurdjumov, Microplitis sp., Oomyzus sokolowskii Kurdjumov, Diadromus collaris(Gravenhorst), Itoplectis naranyae (Ashmead), Exochus sp. and Brachymeria excarinata Gahan. Seven species of hyperparasitoids were also collected. Rates of parasitism of eggs of P. xylostella were usually very low. However, rates of parasitism of larvae and pupae were substantial and showed two peaks each year, around June–July and September–November respectively. Rates of parasitism during peaks were usually 10–60% and reached over 80% on a few occasions. Cotesia plutellae, O. sokolowskii and D. collaris were the major larval, larval-pupal and pupal parasitoids respectively. In the field, C. plutellae was active throughout the year. Oomyzus sokolowskii was active from May to October, entered a quiescent pupal stage in October–November to overwinter and did not emerge until next April–May. Diadromus collariswas recorded from April to July and October. Rates of parasitism of P. xylostellain radish and mustard fields were usually higher than those in cabbage and Chinese cabbage fields in the same locality. Negative correlations of parasitism rates between C. plutellae and O. sokolowskii indicate a competitive relationship for host larvae between these two larval parasitoids.


2011 ◽  
Vol 46 (2) ◽  
pp. 247-253 ◽  
Author(s):  
Tarô Adati ◽  
Wayan Susila ◽  
Ketut Sumiartha ◽  
Putu Sudiarta ◽  
Wataru Toriumi ◽  
...  

2003 ◽  
Vol 38 (1) ◽  
pp. 59-71 ◽  
Author(s):  
Travis A. Hill ◽  
Rick E. Foster

The effects of insecticides on the diamondback moth, Plutella xylostella (L)., and its parasitoid, Diadegma insulare (Cresson), were evaluated in the field. Insecticides applied for control of the diamondback moth caused variations in parasitism by D. insulare ranging from 20 to 84%. Permethrin applications were effective at controlling diamondback moth. Applications of spinosad also resulted in low diamondback moth populations; however, percent parasitism was higher than in untreated plots and over 4× higher than in plots treated with permethrin. Selective materials that conserve D. insulare populations and maintain diamondback moth populations below economic thresholds may reduce the frequency of application, thus prolonging the efficacy of these materials.


2012 ◽  
Vol 65 ◽  
pp. 155-160
Author(s):  
A.J. Michel ◽  
R.C. Butler ◽  
M.M. Davidson

Diamondback moth (Plutella xylostella) (DBM) is a major pest of forage brassica crops in New Zealand This study evaluated the effects of DBM larval feeding on three forage brassica crops in a greenhouse experiment DBM eggs in batches of 5 10 or 50 were placed on 6weekold potted kale rape and turnip plants Plant growth and development (main stem diameter plant height total number of stems and leaves and dry matter weight of roots and foliage (including stems)) were measured at harvest Additionally the number of pupae recovered was recorded None of the measurements of plant growth was influenced (P>005) by DBM egg density Percentage pupal recovery was consistent between treatments Larger DBM population sizes may have been required to show an effect on plant growth Implications of these results for DBM pest management are discussed


2021 ◽  
Author(s):  
Rana M. Sarfraz

Abstract The diamondback moth (DBM) is one of the most studied insect pests in the world, yet it is among the 'leaders' of the most difficult pests to control. It was the first crop insect reported to develop resistance to microbial Bacillus thuringiensis insecticides, and has shown resistance to almost every insecticide, including the most recent groups such as diamide. DBM is a highly invasive species. It may have its origin in Europe, South Africa or East Asia, but is now present wherever its cruciferous hosts exist and is considered to be the most universally distributed Lepidoptera. It is highly migratory and wind-borne adults can travel long distances to invade crops in other regions, countries and continents. Immature stages also hitchhike on plant parts and can establish in new areas. DBM costs the global economy an estimated US$4 -5 billion annually, but its impacts on local biodiversity and habitats in exotic ranges are unknown.


2017 ◽  
Vol 37 (03) ◽  
pp. 163-175 ◽  
Author(s):  
Ruth Kahuthia-Gathu ◽  
Brigitte Nyambo ◽  
Sevgan Subramanian

AbstractCotesia vestaliswas introduced into Kenya from South Africa in March 2003 for biological control ofPlutella xylostellawith initial release in 2004. To confirm establishment, the rate of spread beyond the release sites and parasitism rates byC. vestaliswere assessed between October 2011 and April 2012 in eastern and southeastern Kenya (Kitui, Mwingi/Yatta and Loitokitok areas). Monthly observations on kale infestation by diamondback moth, damage scores, parasitism and parasitoid guild were undertaken on 20 randomly selected plants in farmer-managed kale farms. Sampled larval and pupal stages were placed in containers and taken to the laboratory for parasitoid emergence. The infestation levels ranged from 0.4 to 2.5 DBM per plant, while damage scores ranged from 1.2 to 1.6, which correlated with the infestation levels.Cotesia vestaliswas not only the most abundant parasitoid, but it had also spread to new areas from the release sites. In December, the three sites recorded an average of 50% fromC. vestalis. Excluding the exotic parasitoidsC.vestalisandD. semiclausum, indigenous parasitoids accounted for less than 5% total parasitism. The parasitoid guild of the diamondback moth varied between months and study sites with January recording the highest species diversity and evenness of 1.15 and 0.63, 1.28 and 0.80, 1.08 and 0.47 in Loitokitok, Kitui and Mwingi/Matuu, respectively. Therefore,C.vestalishad an impact on the management of the DBM with parasitism rate of 35% to 88% and had spread beyond the release sites.


2017 ◽  
Vol 43 (2) ◽  
pp. 195
Author(s):  
Robson Thomaz Thuler ◽  
Fernando Henrique Iost Filho ◽  
Hamilton César De Oliveira Charlo ◽  
Sergio Antônio De Bortoli

Plant induced resistance is a tool for integrated pest management, aimed at increasing plant defense against stress, which is compatible with other techniques. Rhizobacteria act in the plant through metabolic changes and may have direct effects on plant-feeding insects. The objective of this study was to determine the effects of cabbage plants inoculated with rhizobacteria on the biology and behavior of diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae). Cabbage seeds inoculated with 12 rhizobacteria strains were sowed in polystyrene trays and later transplanted into the greenhouse. The cabbage plants with sufficient size to support stress were then infested with diamondback moth caterpillars. Later, healthy leaves suffering injuries were collected and taken to the laboratory to feed P. xylostella second instar caterpillars that were evaluated for larval and pupal viability and duration, pupal weight, and sex ratio. The reduction of leaf area was then calculated as a measure of the amount of larval feeding. Non-preference for feeding and oviposition assays were also performed, by comparing the control treatment and plants inoculated with different rhizobacterial strains. Plants inoculated with the strains EN4 of Kluyvera ascorbata and HPF14 of Bacillus thuringiensis negatively affected the biological characteristics of P. xylostella when such traits were evaluated together, without directly affecting the insect behavior.


2021 ◽  
Author(s):  
Yaohui Wang ◽  
Xia Xu ◽  
Xi’en Chen ◽  
Xiaowei Li ◽  
Honglun Bi ◽  
...  

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