Influence of plant sulphur nutrition on oviposition and larval performance of the diamondback moth

We measured adult oviposition preference, larval growth, and feeding behaviour of the crucifer specialist Plutella xylostella (L.) (Lepidoptera: Plutellidae) on plants of Brassica napus (L.) cv. Express (Brassicaceae), grown under three different sulphur regimes. The nutrient solutions used were the following: one sulphur‐free (S₀), one normal sulphur (S_n, normal field concentration), and one sulphur‐rich (S₊, double concentration of S_n). Females laid more eggs on S_n than on S₀ plants, while only a slight, non‐significant difference was observed between S_n and S₊ plants. Moreover, the development time from hatching to emergence was significantly shorter, and adults were heavier on S_n than on S₀ plants. Comparing these same two parameters from S_n and S₊ plants, we found a shorter development time on plants rich in sulphur, although this trend was not statistically significant. Larval feeding preferences were tested in a dual choice assay using leaf discs. A significantly higher number of larvae preferred leaf discs of S_n plants than those of S₀ plants. Furthermore, the larvae preferred S₊ to S_n discs. An optimal supply of sulphur to oilseed rape is necessary for a good seed harvest, and it also plays an important role in acceptance by P. xylostella of the host plant. Maintaining higher levels of sulphur in the plant nutrient solution benefits insect performance, both at the adult and larval stage.     

Importance of host oviposition pattern and plant size for the selection of Trichogramma strains to control the diamondback moth

The aim of this work was to select a candidate strain of Trichogrammatidae (Hymenoptera: Chalcidoidea) to control the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), an important pest of cabbage in Europe. The parasitic efficiency of Trichogramma chilonis Ishii from Japan and Réunion Island, Trichogramma evanescens Westwood from Egypt, Trichogramma ostriniae Pang & Chen from Japan, and Trichogramma semblidis (Aurivillius) from France was studied with sentinel eggs in greenhouse‐grown cauliflower. The percentage of parasitized eggs was measured 1 m from the release point and 3 days after release. Two factors were studied: host‐egg density (three eggs per stem vs. 50 eggs per stem) and plant size (50–100 cm high plants vs. 100–150 cm high plants). Trichogramma evanescens from Egypt achieved the best parasitism. Parasitism efficiency of T. ostriniae from Japan and T. chilonis from Réunion Island was not influenced by egg density. In contrast, parasitism efficiencies of the three other strains were higher at the lower egg density than at the higher egg density. Parasitism efficiency was lower when the plants were bigger, with the exception of T. chilonis from Réunion Island, for which the level of parasitism was not affected by plant size. Thus, T. chilonis from Réunion Island appeared to be the most suitable Trichogramma strain for use in controlling P. xylostella, regardless of the growth stage of the crop. However, T. ostriniae from Japan may also be more suitable for use on cauliflower crops at the early stage of crop development. If potential problems related to the introduction of exotic species are taken into consideration, it is possible to consider the native T. evanescens.     

Dynamics of diamondback moth oviposition in the presence of a highly preferred non-suitable host

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), highly prefers to oviposit on yellow rocket, Barbarea vulgaris (R. Br.) (Cruciferae) var. arcuata, despite larvae not being able to survive on it, suggesting it may have potential as a trap crop. In a no‐choice greenhouse experiment, P. xylostella laid 28% more eggs on B. vulgaris than on cabbage. Within the B. vulgaris plant, P. xylostella laid 3.7 times more eggs on younger than older leaves. Furthermore, we demonstrated that in the presence of B. vulgaris volatiles, P. xylostella laid 23% more eggs on cabbage plants than when B. vulgaris volatiles were absent. Because increased oogenesis in the presence of B. vulgaris could complicate the use of this host as a trap crop for P. xylostella, we wanted to examine levels of oogenesis in varying mixtures of cabbage and B. vulgaris. In outdoor screenhouse experiments, P. xylostella laid a decreasing percentage of eggs on cabbage as the percentage of B. vulgaris increased. However, the total number of eggs laid on cabbage did not differ among treatments, suggesting that the presence of B. vulgaris may have stimulated P. xylostella oviposition. In the field, total oviposition in cabbage plots containing B. vulgaris was 6.3 times higher than in cabbage plots without B. vulgaris. However, in plots with B. vulgaris, P. xylostella laid 99% of the eggs on B. vulgaris and oviposition on cabbage plants was 6.2 times lower than in the plots without B. vulgaris. The results of this study are discussed according to P. xylostella egg‐laying behavior and life history as it relates to its interaction with B. vulgaris.     

Diamondback moth oviposition: effects of host plant and herbivory

The oviposition behaviour of Plutella xylostella L. (Lepidoptera: Plutellidae) on Chinese cabbage (Brassica rapa L. Pekinensis, cv. Wombok), canola (Brassica napus L. cv. Thunder TT), and cabbage (Brassica oleracea L. Capitata, cv. sugarloaf) (Brassicaceae) was studied in the laboratory. In no‐choice experiments moths laid most eggs on the stems and lower three leaves of cabbage plants, the lower three leaves of canola plants, but on the upper three leaves of Chinese cabbage plants. The effects of conspecific herbivore damage to foliage could be replicated by mechanical damage. When foliage was damaged, injured cabbage and canola plants were preferred for oviposition over intact conspecifics, whereas injured Chinese cabbage plants were less preferred than intact conspecifics. However, when root tissue was damaged, intact cabbage and canola plants were preferred over injured conspecifics, whereas moths did not discriminate between root‐damaged and intact Chinese cabbage plants. Injury to upper leaves significantly affected the intra‐plant distribution of eggs. In cabbage and canola plants, injury to leaf 6 significantly increased the number of eggs laid on this leaf, resulting in a significant decrease in the number of eggs laid on the lower foliage/stem of plants, whereas in Chinese cabbage plants it significantly decreased the number of eggs laid on leaf 6. Following oviposition on intact plants, neonate larvae established the vast majority of feeding sites on leaves 5–8 in all three host plants, indicating that larvae moved a considerable distance from preferred oviposition sites in cabbage and canola plants. The growth rate of neonates fed on leaf‐6 tissue was significantly greater than that of those fed on leaf‐1 tissue; >90% of larvae completed development when fed exclusively on leaf‐6 tissue but no larvae completed development when fed exclusively on leaf‐1 tissue. The study demonstrates the complex and unpredictable interactions between P. xylostella and its host plants and provides a basis from which we can begin to understand observed distributions of the pest in Brassica crops.     

Superparasitism and host size effects in Oomyzus sokolowskii, a parasitoid of diamondback moth

Many aspects of a parasitoid's biology may be affected by its host. Host size, for example, could affect parasitoid fitness, especially in gregarious parasitoids, in which the resource is used by multiple siblings. Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae) is a gregarious larval–pupal endoparasitoid of the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), a major pest of crucifers worldwide, and is able to superparasitize the host. This study focuses on the hypothesis that because resource availability is higher in larger hosts, parasitoids developing in larger hosts will fare better. However, superparasitized hosts are expected to yield larger numbers of parasitoid offspring of smaller body size. Results showed that superparasitism increased the number of parasitoid offspring produced per host and increased offspring longevity, but decreased offspring body size. However, developmental time and sex ratio of parasitoid offspring was similar among hosts parasitized once, twice, or three times. Regardless of superparasitism, parasitoids emerging from larger hosts that were fed honey solution lived longer than similarly fed progeny from smaller hosts (36.4 vs. 22.1 days). The results partially support the hypothesis that Oomyzus gained fitness from an increase in host size; moreover, superparasitism seems advantageous for Oomyzus due to increased offspring numbers and longevity.     

The roles of olfaction and vision in host-plant finding by the diamondback moth, Plutella xylostella

Abstract.  The relative roles of olfaction and vision in the crepuscular host-finding process of a major lepidopteran pest of cruciferous crops, the diamondback moth Plutella xylostella are investigated in a series of laboratory and semi‐field experiments. Flying female moths use volatile plant chemical cues to locate and to promote landing on their host, even in complex mixed-crop environments in large cages. Multiple regression analysis shows that both the plant position (front, middle or back rows) and the type of plant (host plant, nonhost plant) are needed to explain the distribution of insects in such a mixed-crop situation. This strong plant position effect indicates that, when host plants are present in a mixture, foraging P. xylostella are more likely to alight on the first row of the plants. The findings are discussed with regard to current theories of host-plant location by phytophagous insects and the possible implications for integrated pest management.     

Effects of insecticides on the foraging behaviour and survival of Cotesia vestalis,a larval parasitoid of the diamondback moth,Plutella xylostella

The effects of the insecticides etofenprox, malathion, diazinon, methomyl, alanycarb, clothianidin and emamectin benzoate on the foraging behaviour and survival of Cotesia vestalis (Hymenoptera: Braconidae), a larval parasitoid of the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) were investigated in the laboratory. The period required for C. vestalis females to reach P. xylostella‐infested Komatsuna (Brassica rapa) plants treated with etofenprox, methomyl or malathion was significantly longer than that to infested plants treated with emamectin benzoate or clothianidin; and the period to reach alanycarb or diazinon‐treated plants was intermediate between them. The period to reach emamectin benzoate‐ or clothianidin‐treated plants was not significantly different from that to distilled water‐sprayed plants, suggesting that etofenprox, methomyl and malathion have strong inhibitory effects on the flight response, whereas the inhibitory effects of alanycarb and diazinon are relatively weak. By contrast, emamectin benzoate and clothianidin showed no inhibitory effect. The time of residency on the clothianidin‐treated plants was significantly longer than that on other insecticide‐treated plants (etofenprox, methomyl, alanycarb, malathion or diazinon), with the time of residency on emamectin benzoate‐treated plants being intermediate between them. These results suggest that etofenprox, methomyl, alanycarb, malathion, and diazinon have a strong inhibitory effect on host‐searching behaviour, while emamectin benzoate and clothianidin have a relatively weak effect. Furthermore, the mortality of wasps after foraging on the clothianidin‐treated plants was significantly higher than after foraging on other insecticide‐treated plants (etofenprox, methomyl or malathion), with subsequent mortality on alanycarb‐, diazinon‐ and emamectin benzoate‐treated plants being intermediate between them. Our results suggest that subsequent mortality increases with decreased inhibitory effect on the foraging behaviour of C. vestalis.     

小菜蛾化学生态学研究现状与展望

本文综述了几种植物吸引或阻抑小菜蛾成虫产卵或幼虫取食的效应。完整的、机械损伤的和菜粉蝶为害的甘蓝类蔬菜释放出数十种醇、醛、酯、酮、硫化物、羧酸类、异硫氰酸酯类和萜烯类挥发性化合物。机械损伤的甘蓝和小菜蛾、菜粉蝶及蜗牛为害的甘蓝释放的挥发物引诱菜粉蝶绒茧蜂。小菜蛾为害甘蓝释放的挥发物引诱菜蛾绒茧蜂。小菜蛾性信息素基本成分是顺 -1 1 -十六碳烯醛和顺 -1 1 -十六碳烯乙酸酯。当顺 -1 1 -十六碳烯醛、顺 -1 1 -十六碳烯乙酸酯和顺 -1 1 -十六碳烯醇以 5∶5∶0 1或顺 -1 1 -十六碳烯醛、顺 -1 1 -十六碳烯乙酸酯、顺 -1 1 -十六碳烯醇和顺 -9-十四碳烯乙酸酯按70∶3 0∶1∶0 0 1比例制成的诱芯诱蛾效果较好。宜深入探究寄主植物—小菜蛾—菜蛾绒茧蜂间的通讯机制 ,开发高效诱芯。     

Temporal changes in olfactory and oviposition responses of the diamondback moth to herbivore‐induced host plants

Temporal changes in the pre‐ and post‐alighting responses of mated female diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), to two species of Brassica (Brassicaceae) host plants induced by larval feeding were studied using olfactometer and oviposition assays. Females displayed strong olfactory and oviposition preferences for herbivore‐induced common cabbage (Brassica oleracea var. capitata L. cv. sugarloaf) plants over intact plants; these preferences decreased with time and disappeared by the 7th day after induction. In herbivore‐induced common cabbage plants, eggs were clustered near feeding damage on the younger leaves (leaves 5–7), whereas in intact plants, eggs were clustered on the stem and lower leaves (leaves 1–4) . However, as the time interval between larval feeding and oviposition increased, more eggs were laid on the lower leaves of induced plants. This demonstrates a change in egg distribution from the pattern associated with induced plants to that associated with intact plants. In contrast, females displayed strong olfactory and oviposition preferences for intact Chinese cabbage [Brassica rapa ssp. pekinensis (Lour.) Hanelt cv. Wombok] plants over induced plants; these preferences decreased with time and disappeared by the 5th day after induction. More eggs were laid on the upper leaves (leaves 4–6) than on the lower leaves (leaves 1–3) of intact Chinese cabbage plants at first, but the distribution changed over time until there were no significant differences in the egg count between upper and lower leaves by the 4th day post induction. For both host plant species, pre‐alighting responses of moths were reliable indicators of post‐alighting responses on the first 2 days post induction. The results suggest that temporal changes in a plant's profile (chemical or otherwise) following herbivory may influence attractiveness to an insect herbivore and be accompanied by changes in olfactory and oviposition preferences.     

Initiation of fungal epizootics in diamondback moth populations within a large field cage: proof of concept for auto-dissemination

Adult diamondback moths (DBM), Plutella xylostella L. (Lepidoptera: Plutellidae), inoculated with the fungus Zoophthora radicans, were released within a large field cage containing DBM‐infested potted broccoli plants. Larvae and pupae on exposed and caged control plants were examined on five occasions over the next 48 days for evidence of Z. radicans infection. Infected larvae were first detected on exposed plants 4 days after the initial release of adults, and after 48 days the infection level reached 79%. Aerially borne conidia were a factor in transmission of the fungus. Infection had no effect on possible losses of larval and adult cadavers due to scavengers in field crops. In a trial to measure the influence of infection on dispersal, twice as many non‐infected as infected males were recaptured in pheromone traps, although the difference in cumulative catch only became significant 3 days after release of the males. In a separate experiment, when adult moths were inoculated with Beauveria bassiana conidia and released into the field cage, DBM larvae collected from 37 of 96 plants sampled 4 days later subsequently died from B. bassiana infection. The distribution of plants from which the infected larvae were collected was random, but the distribution of infected larvae was clustered within the cage. These findings suggest that the auto‐dissemination of fungal pathogens may be a feasible strategy for DBM control, provided that epizootics can be established and maintained when DBM population densities are low.     

Trap cropping effect on oviposition behaviour of the leek moth Acrolepiopsis assectella and the diamondback moth Plutella xylostella

The potential of trap cropping as a pest control strategy was explored for two specialist moth species, where oviposition behaviour determines larval distribution. Oviposition behaviour was studied at three different scales: Individual plants in the laboratory, small scale field experiments with and without cages, and medium scale field trials. The study insects were the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), a specialist on Brassica species and the leek moth, Acrolepiopsis assectella (Z.) (Lepidoptera: Acrolepiidae), a specialist on Allium species. The diamondback moth preferred Indian mustard, Brassica juncea (L.) over white cabbage, B. oleracea var alba (L.). The leek moth did not show preference when offered leek, Allium porrum (L.) and chives, A. schoenoprasum (L.). However, the leek moth did prefer to oviposit on plants of a larger biomass over smaller plants. In both the small scale and the medium scale field studies the trap crops reduced the number of eggs laid on the primary crop. The total number of eggs laid in the monoculture and the trap crop treatments were the same in the small scale field cage study, but the females distributed their eggs differently. More eggs were laid on trap crops compared with primary crops and this pattern was also validated in the medium scale field trials. In this study only the direct effects of trap cropping were considered. Indirect effects of vegetation diversity such as enhancement of natural enemies could potentially increase the efficacy of trap cropping.     

亚麻荠对小菜蛾幼虫取食和成虫行为反应的影响

亚麻荠是一种很少有害虫危害的油料作物。用室内生测和Y 型嗅觉仪研究了亚麻荠对小菜蛾Plutella xylostella幼虫取食和成虫行 为反应的影响。以甘蓝作对照,用亚麻荠叶片喂养的小菜蛾初孵幼虫3天后校正死亡率为79 .2%,显示了较强的致死作用;喂养小菜蛾3龄幼虫至化蛹,其存活率、化蛹率、蛹重及成 虫寿命都显著降低,表明亚麻荠对小菜蛾幼虫的生长发育有不利影响。在幼虫的取食选择实 验中,有甘蓝叶供选择时,小菜蛾幼虫不取食亚麻荠;在无可选择的情况下,小菜蛾幼虫也 取 食亚麻荠叶片,但取食量很小,与取食甘蓝叶的量相比,差异极显著。行为反应测试表明, 小菜蛾成虫对甘蓝和亚麻荠植株的挥发物都有明显的趋性反应,与对照（净化空气）相比, 差异极显著,而在甘蓝和亚麻荠之间无选择性。说明小菜蛾成虫对亚麻荠植株的挥发物具有 较强的定向反应。     

Trap cropping effect on oviposition behaviour of the leek moth Acrolepiopsis assectella and the diamondback moth Plutella xylostella

The potential of trap cropping as a pest control strategy was explored for two specialist moth species, where oviposition behaviour determines larval distribution. Oviposition behaviour was studied at three different scales: Individual plants in the laboratory, small scale field experiments with and without cages, and medium scale field trials. The study insects were the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), a specialist on Brassica species and the leek moth, Acrolepiopsis assectella (Z.) (Lepidoptera: Acrolepiidae), a specialist on Allium species. The diamondback moth preferred Indian mustard, Brassica juncea (L.) over white cabbage, B. oleracea var alba (L.). The leek moth did not show preference when offered leek, Allium porrum (L.) and chives, A. schoenoprasum (L.). However, the leek moth did prefer to oviposit on plants of a larger biomass over smaller plants. In both the small scale and the medium scale field studies the trap crops reduced the number of eggs laid on the primary crop. The total number of eggs laid in the monoculture and the trap crop treatments were the same in the small scale field cage study, but the females distributed their eggs differently. More eggs were laid on trap crops compared with primary crops and this pattern was also validated in the medium scale field trials. In this study only the direct effects of trap cropping were considered. Indirect effects of vegetation diversity such as enhancement of natural enemies could potentially increase the efficacy of trap cropping.     

Occurrence of diamondback moth,Plutella xylostella (Lepidoptera: Plutellidae), and its larval parasitoids across Saskatchewan,Canada

The prevalence of the diamondback moth and its larval parasitoids, was explored across Saskatchewan, Canada. Higher numbers of diamondback moths were recorded early in the season than later and in the Mixed Grassland compared to three other ecoregions. The highest proportion of parasitism was observed in the Boreal Transition ecoregion in early season.     

cDNA characterization and expression analysis of two arylphorin-like hexameric protein genes from the diamondback moth, Plutella xylostella (L.)

We cloned and characterized two hexameric storage protein genes, PxAry1 and PxAry2, from Plutella xylostella and investigated the expression pattern in different developmental stages and in response to treatment by a juvenile hormone (JH) analog. The complete coding sequences of PxAry1 and PxAry2 are comprised of 2,097 and 2,094 bp with 699 and 698 amino acid residues, respectively. Signal peptides of 16 amino acids are predicted at the N-termini. According to both the phylogenetic analysis and amino acid composition (>16% aromatic amino acids), PxAry1 and PxAry2 belong to the arylphorin-like protein genes. Analysis using Northern hybridization and RT-PCR showed varying levels of genes expression in the developmental stages with a small difference between sexes. Expression of both genes in fourth instar larvae was suppressed after treatment with a JH-analog. Southern hybridization revealed the presence of multiple arylphorin genes in the genome.     

小菜蛾抗药性及其治理对策的研究进展

小菜蛾（Plutella xylostella L.）的抗药性研究是一项全球性的重要课题。本从其抗药性发展、抗药性机理研究进展、抗药性检测及研究手段的状况、抗药性治理对策等方面,对小菜蛾抗药性的研究进展进行综述。目前,对小菜蛾抗药性的分子水平上的探讨甚少。     

玫烟色拟青霉对小菜蛾致病力的时间-剂量-死亡率模型模拟

小菜蛾Plutella xylostella是我国南方十字花科蔬菜上的重要害虫,已对田间常用的化学杀虫剂产生了严重的抗性。为寻找有效的小菜蛾生物防治措施,本实验研究了一株分离自家白蚁的玫烟色拟青霉Paecilomyces fumosoroseus (SCAU-PFCF01)对小菜蛾2～4龄幼虫的致病力。实验采用浸液法,供试浓度为1×10³、1×10⁴、1×10⁵、1×10⁶和1×10⁷个孢子/mL。结果表明：随玫烟色拟青霉孢子浓度的升高,小菜蛾的感病死亡率增加,在浓度为1×10⁷ /mL时,小菜蛾2、3和4龄幼虫的累计死亡率分别为96%、85%和80%。玫烟色拟青霉对小菜蛾各龄幼虫的致病力与供试龄期有关,其感病的敏感顺序为2龄、3龄和4龄。用时间 剂量 死亡率模型（time-dose-mortality model,TDM）对各龄幼虫的致病力数据进行模拟,所建模型均顺利通过Hosmer-Lemeshow拟合异质性检验,表明模型拟合良好,并由模型估计出了该菌株对小菜蛾各龄幼虫的致死剂量与致死时间。2龄幼虫接种后第7天、3龄幼虫接种后第5天、4龄幼虫接种后第4天的LC₅₀估计值分别为1.17×10⁴、1.44×10⁴和5.21×10⁴ /mL,LC₉₀估计值分别为1.98×10⁶、3.82×10⁷和1.29×10⁸ /mL。玫烟色拟青霉对小菜蛾幼虫的致死时间与浓度相关,供试各龄幼虫的LT₅₀值随着孢子悬浮液浓度的增加而递减,在1×10⁵～1×10⁷ /mL的范围内,2龄幼虫的LT₅₀值从3.16天降低到1.72天,3龄幼虫的LT₅₀从3.21天降低到1.83天,4龄幼虫的LT₅₀从3.69天降低到2.04天。即2龄幼虫致死所需的时间最短,其次为3龄幼虫,4龄幼虫致死所需的时间最长。结果显示了该株玫烟色拟青霉在小菜蛾的生物防治中具较强的应用潜力。     

亚精胺对小菜蛾幼虫生长及保护酶活力的影响

在实验室条件下测定经亚精胺处理后,对小菜蛾Plutella xylostella L.3龄幼虫取食量、存活、羽化率、蛹重及保护酶活力的影响。结果表明,亚精胺对小菜蛾幼虫的取食量、存活、羽化及保护酶活力均有明显的影响。经过亚精胺处理后的大部分时间段,3龄幼虫的取食量、存活率、化蛹率及体内SOD和POD活力均明显高于蒸馏水对照;对处理后24和36h CAT活力也有明显的促进作用;但亚精胺对其蛹重、蛹的羽化率却无明显的影响。     

腐胺对小菜蛾幼虫生长及保护酶活力的影响

在实验室条件下测定腐胺处理对小菜蛾Plutella xylostella (L.) 3龄幼虫取食量、存活、羽化率、蛹重及保护酶活力的影响。结果表明,腐胺对小菜蛾幼虫的取食量、存活、羽化及保护酶活力均有明显的影响。经过腐胺处理后,3龄幼虫的取食量、存活率、化蛹率及体内SOD和POD活力均明显高于蒸馏水对照;但腐胺对其蛹重、蛹的羽化率及体内CAT活力却无明显的影响。     

Influence of cabbage resistance and colour upon the diamondback moth and its parasitoid Oomyzus sokolowskii

Host plant resistance and biological control are vital integrated pest management tools against the diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), but to date no study has investigated this system including the DBM parasitoid Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae). We examined oviposition and development of P. xylostella exposed to two commercial cabbage cultivars (green ‘Chato de quintal’ and red ‘Roxo’) and possible effects upon O. sokolowskii. Under free‐choice tests, DBM females laid significantly more eggs on plants of the green cabbage, even though several population growth parameters showed that DBM developed better on the red cabbage. Furthermore, a laboratory free‐choice test with artificially green‐ and red‐painted kale leaf discs demonstrated a similar oviposition preference pattern, with green colour being preferred over red colour. The preference was apparently visually mediated; olfactometer tests showed similar attraction of moths to both green and red cultivars in choice and non‐choice tests. Host plant cultivar had no statistically significant effect on female parasitoid behaviour towards DBM larvae, nor on parasitoid numbers or longevity. Moreover, wasps parasitizing DBM larvae reared on the green cultivar developed more quickly and in larger numbers per parasitized larva. Thus, feeding on green cabbage rather than red does not hinder, and potentially even enhances, control of DBM by O. sokolowskii. On a practical level, these results suggest that intercalating green cabbage cultivars as a trap crop might help protect more profitable red cultivars in growing fields.