Cauliflower Plants Research Articles

Colonization of lettuce cultivars and rotation crops by Fusarium oxysporum f. sp. lactucae, the cause of fusarium wilt of lettuce

The severity of fusarium wilt is affected by inoculum density in soil, which is expected to decline during intervals when a non‐susceptible crop is grown. However, the anticipated benefits of crop rotation may not be realized if the pathogen can colonize and produce inoculum on a resistant cultivar or rotation crop. The present study documented colonization of roots of broccoli, cauliflower and spinach by Fusarium oxysporum f. sp. lactucae, the cause of fusarium wilt of lettuce. The frequency of infection was significantly lower on all three rotation crops than on a susceptible lettuce cultivar, and the pathogen was restricted to the cortex of roots of broccoli. However, F. oxysporum f. sp. lactucae was isolated from the root vascular stele of 7·4% of cauliflower plants and 50% of spinach plants that were sampled, indicating a greater potential for colonization and production of inoculum on these crops. The pathogen was also recovered from the root vascular stele of five fusarium wilt‐resistant lettuce cultivars. Thus, disease‐resistant plants may support growth of the pathogen and thereby contribute to an increase in soil inoculum density. Cultivars that were indistinguishable based on above‐ground symptoms, differed significantly in the extent to which they were colonized by F. oxysporum f. sp. lactucae. Less extensively colonized cultivars may prove to be superior sources of resistance to fusarium wilt for use in breeding programmes.

THE SESONAL ACTIVITY OF THE MAIN INSECT PARASITOIDS ATTACKING PUPAL STAGE OF THE CABBAGE BUTTERFLY Pieris rapae L. ON DIFFERENT HOST PLANTS.

The experiment was carried out at the experimental farm of the Plant Protection Department Sakha Agriculture Research Station, Kafr El-Sheikh, during three successive vegetable growing seasons, 2011/12and 2012/13 on cabbage (Brassica oleracea var. capitata L.), cauliflower (B. oleracea var. botrytis L.), and Canola rape (Brassica napu. oleifera L ). Cabbage plants harboured the highest average percentage of the pupal parasitoids Brachymeria femorata parasitoid during three successive seasons 2011 , 2012 and 2013 represented by 17.5and 18.3% followed by cauliflower plants 13.9 and 14.9 %.While, canola plants recorded the last category and represented by 11.6and 13.9%,respectively .Moreover, there was a highly significant differences between the percentage of B.femorata parasitoids on different cruciferous plants during the two successive seasons .The cabbage plants harboured the highest average percentage of Pteromalus puparum during the three successive seasons 2011/12 and 2012/13 represented by 30.8% and 31.5% followed by cauliflower plants 24.4and 26.6% while, canola plants recorded the last category and represented by 19.6% and 14.7%,respectively .Moreover there were a highly significant differences between the percentage of P. puparum on different cruciferous plants during the two successive seasons. Cabbage plants harboured the highest average percentage of Phryxe vulgaris during three successive seasons 2011/12 and 2012/13 and represented by 8.9% and 8.1% followed by cauliflower plants 5.8and 6.8% while, canola plants recorded the last category and represented by 3.5% and 2.9 % , respectively.Moreover, there were a highly significant differences between the percentage of P. vulgaris on different cruciferous plants during the two successive seasons.

Diel Activity and Behavior of <I>Bagrada hilaris</I> (Hemiptera: Pentatomidae) on Desert Cole Crops

Patterns of diel activity and behavior of the Bagrada bug, Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae), were investigated in a series of field and greenhouse experiments in Yuma, AZ. Adults of B. hilaris were monitored by on-site direct observation on broccoli and cauliflower plants in large-block experimental plots at various intervals throughout consecutive 24-h periods. In the field trials, mean number of B. hilaris adults differed among sampling times, with peak abundance observed consistently between 1300 and 1800 hours. There was a positive correlation between temperature and numbers ofB. hilaris adults in all fields, and a negative relationship between humidity and adult numbers in 7 of 12 fields. Significant relationships between temperature and B. hilaris numbers were revealed in regression models for all trials. Slopes were not significantly different among all broccoli blocks or in three of the four cauliflower fields. In greenhouse studies, mating occurred throughout the day but peaked between 1000 and 1600 hours. Females of B. hilaris caused more feeding damage than males on the first true leaf of broccoli, and additional differences in behavior between sexes were observed. Our results suggest that higher temperatures increase field activity and influence the behavior of adult B. hilaris, and temperature is a more reliable indicator to predict the activity of B. hilaris than other environmental parameters measured. The implications of these findings for developing monitoring and management programs for B. hilaris in cruciferous crops are discussed.

Enhanced Resistance toSpodoptera liturain Endophyte Infected Cauliflower Plants

Endophytic fungi, which live within host plant tissues without causing any visible symptom of disease, are important mediators of plant-herbivore interactions. These endophytes enhance resistance of host plant against insect herbivores mainly by productions of various alkaloid based defensive compounds in the plant tissue or through alterations of plant nutritional quality. Two endophytic fungi, i.e., Nigrospora sp. and Cladosporium sp., were isolated from Tinospora cordifolia (Thunb.) Miers, a traditional indian medicinal plant. Cauliflower (Brassica oleracea L.) plants were inoculated with these two endophytic fungi. The effect of endophyte infected and uninfected cauliflower plants were measured on the survival and development of Spodoptera litura (Fab.), a polyphagous pest. Endophyte infected cauliflower plants showed resistance to S. litura in the form of significant increase in larval and pupal mortality in both the fungi. Inhibitory effects of endophytic fungi also were observed on adult emergence, longevity, reproductive potential, as well as hatchability of eggs. Thus, it is concluded that antibiosis to S. litura could be imparted by artificial inoculation of endophytes and this could be used to develop alternative ecologically safe control strategies.

Flower infection of Brassica oleracea with Xanthomonas campestris pv. campestris results in high levels of seed infection

During seed production, Brassica seed may become infected with Xanthomonas campestris pv. campestris after systemic colonization of plants upon leaf infection, or alternatively, after flower infection. Polytunnel experiments were conducted in 2007 and 2008 to study the relative importance of these colonization routes resulting in seed infection. Cauliflower plants (Brassica oleracea) were spray-inoculated at the 8-leaf stage, after formation of cauliflowers or during flowering, at which stage leaves or blossoms were inoculated. Inoculation at all stages resulted in a relatively high percentage of systemic infection; the average estimated infection incidences for stem base and peduncle infections were 16 % and 19 %, respectively. When seed samples were examined by dilution plating for deep-seated infection following hot water treatment, Xcc was detected in 61 % of the 23 seed samples harvested from plants with inoculated flowers. However, symptom development in seedlings raised from the seeds could not be confirmed in a grow-out test under favourable conditions for Xcc infection at a high RH (>95 %) and a relative high temperature (28 °C). Xcc was not detected in 59 seed samples harvested from leaf-inoculated plants with the exception of one sample from plants inoculated at peduncle formation. In a third polytunnel experiment carried out in 2009, the population dynamics of Xcc on inoculated flowers was investigated. Following spray-inoculation of flowers, 52 % of the flowers were infected with Xcc. During development of siliques, infection incidence decreased slowly and at 56 dpi, 20 % of the superficially disinfected siliques were infected with Xcc. It was estimated that 0.18 % of the seeds was infected and that 1–10 % of the infected siliques contained infected seeds. The implications of these results for control of Xcc in a seed production crop are discussed.

Universality of cauliflower-like fronts: from nanoscale thin films to macroscopic plants

Chemical vapor deposition (CVD) is a widely used technique to grow solid materials with accurate control of layer thickness and composition. Under mass-transport-limited conditions, the surface of thin films thus produced grows in an unstable fashion, developing a typical motif that resembles the familiar surface of a cauliflower plant. Through experiments on CVD production of amorphous hydrogenated carbon films leading to cauliflower-like fronts, we provide a quantitative assessment of a continuum description of CVD interface growth. As a result, we identify non-locality, non-conservation and randomness as the main general mechanisms controlling the formation of these ubiquitous shapes. We also show that the surfaces of actual cauliflower plants and combustion fronts obey the same scaling laws, proving the validity of the theory over seven orders of magnitude in length scales. Thus, a theoretical justification is provided, which had remained elusive so far, for the remarkable similarity between the textures of surfaces found for systems that differ widely in physical nature and typical scales.

PEMANFAATAN BAKTERI ENTOMOPATOGENIK Bacillus cereus TERHADAP HAMA Spodoptera litura PADA TANAMAN KUBIS

ABSTRACT This study aims to obtain entomopatogenik bacteria (Bacillus cereus) as a potential biological control of pests Spodoptera litura and determine the morphological characteristics and the potential power to kill isolate B. cereus. Explored endogenous bacteria from 99 soil samples from Minahasa regency, South Minahasa and Tomohon. Bacteria were isolated by selectively using methods Ohba and Aizawa identified by colony and cell morphology. The results showed that of the 99 soil samples obtained 141 isolates were identified as Bacillus cereus. Screening 141 isolates of the 80 isolates contained S.litura larvae that can cause deadly diseases and test larvae >50% after 96 hours with a dose of inoculum 1.5 x 107 spores / ml. Isolates that could potentially then be selected based on the pathogenicity then be developed into a biopesticide for pest control S. litura on cauliflower and broccoli plants. Keywords: Entomoopatogenic bacteria, Spodoptera litura, cabbage plants

Cauliflower stunt associated with a phytoplasma of subgroup 16SrIII-J and the spatial pattern of disease

Since 2000, a disease has occurred with high levels of incidence in crops of cauliflower grown in the green belt area of the city of Sao Paulo, Brazil. The symptoms are characterized by stunting, malformation of the inflorescence, reddening leaves, and vascular necrosis, suggesting infection by phytoplasma. These symptoms are similar to those described in Brassicas species affected by the aster yellows (16SrI) group of phytoplasma. In the present study, a phytoplasma from the 16SrIII-J subgroup was identified in cauliflower plants based on actual and virtual RFLP patterns and phylogenetic analysis, and was distinct from the phytoplasmas frequently associated with aster yellows disease in Brassicas. Pathogenicity assays using dodder confirmed that the identified phytoplasma is the agent of the observed disease, which is here designated as cauliflower stunt. Consequently, this species of Brassica may be recognized as a new host for subgroup 16SrIII-J, which has frequently been found in diverse species cultivated in Brazil. The spatial pattern of diseased plants was determined in ten cauliflower plots of 300 to 728 plants each. All plants in these plots were evaluated by visual assessments, assigned as diseased or healthy and mapped. The dispersion index and Taylor’s power law were determined for various quadrat sizes and the results showed that the diseased plants were distributed in a random pattern in fields with a low disease incidence and in an aggregated pattern in fields with a disease incidence greater than 25 %. According to an isopath area analysis, diseased plants were predominantly present in the field borders, suggesting that the pathogen is possibly introduced by vector(s) from the external area.

Dynamics of chlorpyrifos residues in cauliflower cultivation fadeDynamika zanikania pozostałości chloropiryfosu w uprawie kalafiora

Studies on the decay of chloropyrifos residue (Dursban 480 EC) in cauliflower were carried out in 2011. Two variants of spraying treatment were tested – the preparation was applied once and twice to cauliflower plants under the field conditions. A total of 50 samples of leaves and mature roses were analysed. The level of chloropyrifos residues detected in the plant material ranged from 0.01 to 0.006 mg/kg (after one treatment) and 0.005 mg/kg (after two treatments). In general, the level of detected residues of the preparation did not exceed 0.01 mg/kg.

Phenological and Phytochemical Changes Correlate with Differential Interactions ofVerticillium dahliaewith Broccoli and Cauliflower

Cauliflower (Brassica oleracea var. botrytis subvar. cauliflora) is susceptible to wilt caused by Verticillium dahliae but broccoli (B. oleracea var. italica subvar. cyamosa) is not. Infection of broccoli and cauliflower by a green fluorescent protein-expressing isolate of V. dahliae was examined using epifluorescence and confocal laser-scanning microscopy to follow infection and colonization in relation to plant phenology. Plant glucosinolate, phenolic, and lignin contents were also assayed at 0, 4, 14, and 28 days postinoculation. V. dahliae consistently infected and colonized the vascular tissues of all cauliflower plants regardless of age at inoculation, with the pathogen ultimately appearing in the developing seed; however, colonization decreased with plant age. In broccoli, V. dahliae infected and colonized root and stem xylem tissues of plants inoculated at 1, 2, or 3 weeks postemergence. However, V. dahliae colonized only the root xylem and the epidermal and cortical tissues of broccoli plants inoculated at 4, 5, and 6 weeks postemergence. The frequency of reisolation of V. dahliae from the stems (4 to 22%) and roots (10 to 40%) of mature broccoli plants was lower than for cauliflower stems (25 to 64%) and roots (31 to 71%). The mean level of aliphatic glucosinolates in broccoli roots was 6.18 times higher than in the shoots and did not vary with age, whereas it was 3.65 times higher in cauliflower shoots than in the roots and there was a proportional increase with age. Indole glucosinolate content was identical in both cauliflower and broccoli, and both indole and aromatic glucosinolates did not vary with plant age in either crop. Qualitative differences in characterized glucosinolates were observed between broccoli and cauliflower but no differences were observed between inoculated and noninoculated plants for either broccoli or cauliflower. However, the phenolic and lignin contents were significantly higher in broccoli following inoculation than in noninoculated broccoli or inoculated cauliflower plants. The increased resistance of broccoli to V. dahliae infection was related to the increase in phenolic and lignin contents. Significant differential accumulation of glucosinolates associated with plant phenology may also contribute to the resistant and susceptible reactions of broccoli and cauliflower, respectively, against V. dahliae.

Technology of In Vitro production of dihaploid Brassica plants

The conditions of cultivating isolated anthers and microspores are optimized for the purpose of producing haploid rapeseed, white head cabbage, and cauliflower plants under in vitro conditions and the process of direct embryogenesis is studied. It is established that the presence of 1 mg/l kinetin and 1 mg/l naphthaleneacetic acid hormones in nutrient medium B5 stimulated the process of direct embryogenesis in rapeseed as well as the formation of secondary and tertiary embryoids on hypocotyl and leaf segments of sterile sprouts. A cytological analysis of regenerant plants (count of the number of chloroplasts in stomatal guard cells and chromosomes in root meristem) confirmed the haploid nature of the rapeseed plants. Regenerants are obtained from callus tissue of cabbage microspores.

The cauliflower Orange gene enhances petiole elongation by suppressing expression of eukaryotic release factor 1

The cauliflower (Brassica oleracea var. botrytis) Orange (Or) gene affects plant growth and development in addition to conferring β-carotene accumulation. This study was undertaken to investigate the molecular basis for the effects of the Or gene mutation in on plant growth. The OR protein was found to interact with cauliflower and Arabidopsis eukaryotic release factor 1-2 (eRF1-2), a member of the eRF1 family, by yeast two-hybrid analysis and by bimolecular fluorescence complementation (BiFC) assay. Concomitantly, the Or mutant showed reduced expression of the BoeRF1 family genes. Transgenic cauliflower plants with suppressed expression of BoeRF1-2 and BoeRF1-3 were generated by RNA interference. Like the Or mutant, the BoeRF1 RNAi lines showed increased elongation of the leaf petiole. This long-petiole phenotype was largely caused by enhanced cell elongation, which resulted from increased cell length and elevated expression of genes involved in cell-wall loosening. These findings demonstrate that the cauliflower Or gene controls petiole elongation by suppressing the expression of eRF1 genes, and provide new insights into the molecular mechanism of leaf petiole regulation.

Effect of Insect Density, Plant Age, and Residue Duration on Acetamiprid Efficacy Against Swede Midge

The Swede midge, Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae), a common insect pest in Europe, is a newly invasive pest in North America that constitutes a major threat to crucifer vegetable and field crops. Chemical control of Swede midge with synthetic insecticides under laboratory conditions indicated that insecticides generally could provide very effective control; however, insecticide treatments in the field were rarely able to maintain damage levels within marketable limits. In the current study, factors affecting insecticide efficacy were investigated using a neonicotinoid insecticide, acetamipird, as a foliar spray on cauliflower plants. Our results indicated that Swede midge density did not affect the efficacy of acetamirpid, although it significantly increased the subsequent Swede midge population on the unsprayed cauliflower plants. Additionally, cauliflower plant age did not significantly affect spray coverage and acetamipird efficacy on Swede midge. However, acetamiprid only provided 6-d control of Swede midge and its efficacy was reduced by up to 50% 9 d after spraying. Implications of our results on the development of an overall integrated pest management (IPM) program for Swede midge also are discussed.

Effects of limestone applications on soil pH and extractable elements in a cauliflower field study

The pH and Mehlich-3 extractable concentrations of a variety of elements including those that were study treatments (Ca, Mn and Zn) and those that were expected to be influenced by the treatments (Mg, Sr, K, Rb, Na, Al, Fe, Si and Cu) were determined in soil samples from a cauliflower field trial conducted between 1979 and 1985. The treatments were limestone applied to the soil at three rates (0, 9 and 19 Mg ha-1) and Zn and Mn foliar applications. The pH of air-dried samples varied only slightly when analysed within each year of sampling versus as one batch after the trial was completed, which showed that the samples were stable over the long time the samples had to be stored through the field trial period and until the samples were analysed. Being able to do all the analyses in one batch also facilitated the application of quality control to ensure comparability of results. There were differences in the soil measurements of most of the elements taken pre-plant versus post-harvest, showing that the time of sampling must be consistent for experimental and soil test interpretations. Post-harvest samples (i.e., focusing on residual effects of limestone application) were selected to examine the treatment effects. Limestone application had wide-ranging and variable effects on extractable elements in the soil. Soil pH and extractable Ca increased with increased limestone rate as expected, while the amount of extractable Mn, Zn, K, Mg, Na, Al and Fe decreased. Extractable Sr, Si and Cu increased with limestone applications. Extractable Ca, Zn, Mg, Al and Si were affected to 15-30 cm depth, and pH and extractable Mn, Rb and Fe were affected to 30-60 cm. Subsurface (>15 cm depth) Sr, K, Na and Cu were not influenced by the limestone treatments. The effect of limestone on the elements tended to correspond to the effect previously observed on the contents of these elements in cauliflower plants. The ability of Mehlich-3 extract solution to reflect the availability of elements to plants and the effect of limestone applications on other elements simultaneously showed the potential for this soil test solution to predict the need for nutrient amendments to prevent lime-induced deficiencies.

Spectral indicators for salinity effects in crops: a comparison of a new green indigo ratio with existing indices

Spectroradiometric measurements were taken from eggplant (Solanum melongena) and cauliflower (Brassica oleracea) plants in a controlled experiment treated with sodium chloride (NaCl) concentrations between 30 and 150 mmol. Assessment of seven vegetation indices indicated potential difference between three levels of salinity in effects, with the green indigo ratio (GIR of reflectance of 554 and 436 nm) yielding the most consistent results. Salinity effects started from the second week, but the highest differences were obtained in the fourth week for cauliflower and in the third and sixth weeks for eggplant.

The Purple Cauliflower Arises from Activation of a MYB Transcription Factor

Anthocyanins are responsible for the color of many flowers, fruits, and vegetables. An interesting and unique Purple (Pr) gene mutation in cauliflower (Brassica oleracea var botrytis) confers an abnormal pattern of anthocyanin accumulation, giving the striking mutant phenotype of intense purple color in curds and a few other tissues. To unravel the nature of the Pr mutation in cauliflower, we isolated the Pr gene via a combination of candidate gene analysis and fine mapping. Pr encoded a R2R3 MYB transcription factor that exhibited tissue-specific expression, consistent with an abnormal anthocyanin accumulation pattern in the mutant. Transgenic Arabidopsis (Arabidopsis thaliana) and cauliflower plants expressing the Pr-D allele recapitulated the mutant phenotype, confirming the isolation of the Pr gene. Up-regulation of Pr specifically activated a basic helix-loop-helix transcription factor and a subset of anthocyanin structural genes encoding flavonoid 3'-hydroxylase, dihydroflavonol 4-reductase, and leucoanthocyanidin dioxygenase to confer ectopic accumulation of pigments in the purple cauliflower. Our results indicate that the genetic variation including a Harbinger DNA transposon insertion in the upstream regulatory region of the Pr-D allele is responsible for the up-regulation of the Pr gene in inducing phenotypic change in the plant. The successful isolation of Pr provides important information on the regulatory control of anthocyanin biosynthesis in Brassica vegetables, and offers a genetic resource for development of new varieties with enhanced health-promoting properties and visual appeal.

Occurrence and Diversity of Xanthomonas campestris pv. campestris in Vegetable Brassica Fields in Nepal.

Black rot caused by Xanthomonas campestris pv. campestris was found in 28 sampled cabbage fields in five major cabbage-growing districts in Nepal in 2001 and in four cauliflower fields in two districts and a leaf mustard seed bed in 2003. Pathogenic X. campestris pv. campestris strains were obtained from 39 cabbage plants, 4 cauliflower plants, and 1 leaf mustard plant with typical lesions. Repetitive DNA polymerase chain reaction-based fingerprinting (rep-PCR) using repetitive extragenic palindromic, enterobacterial repetitive intergenic consensus, and BOX primers was used to assess the genetic diversity. Strains were also race typed using a differential series of Brassica spp. Cabbage strains belonged to five races (races 1, 4, 5, 6, and 7), with races 4, 1, and 6 the most common. All cauliflower strains were race 4 and the leaf mustard strain was race 6. A dendrogram derived from the combined rep-PCR profiles showed that the Nepalese X. campestris pv. campestris strains clustered separately from other Xanthomonas spp. and pathovars. Race 1 strains clustered together and strains of races 4, 5, and 6 were each split into at least two clusters. The presence of different races and the genetic variability of the pathogen should be considered when resistant cultivars are bred and introduced into regions in Nepal to control black rot of brassicas.

Parasitism of different Trichogramma species and strains on Plutella xylostella L. on greenhouse cauliflower

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the most important pest of cultivated Brassica worldwide, including those grown in greenhouses like cauliflower. In this article, we evaluate the potential of various species (and various strains of some species) of Trichogrammatidae (Hymenoptera: Chalcidoidea) to control this pest on cauliflower in greenhouse in France. We assessed the parasitism levels on P. xylostella of 17 Trichogrammatidae strains, belonging to 12 different species (2 indigenous strains from France), under greenhouse conditions. Parasitism levels for each of the Trichogrammatidae species and strains were determined on cauliflower leaves (Brassica oleraceabotrytis L., Brassicaceae) infested with P. xylostella eggs. Nine strains parasitized 60% (or more) of the P. xylostella eggs. Compared to previous results in laboratory conditions, climatic conditions of the greenhouse did not influence parasitism levels. The presence of the cauliflower plants may have a positive effect on eight strains, a negative effect on four strains and no effect on five strains. Our study points out the importance of including the host plant of P. xylostella when conducting studies aiming to select the most efficient parasitoid against this pest.

Testing and improving the effectiveness of trap crops for management of the diamondback moth Plutella xylostella (L.): a laboratory‐based study

The aim of this study was to assess white mustard (Sinapis alba L.) as a trap crop for diamondback moth [Plutella xylostella (L.)] on cauliflower [Brassica oleracea (L.) var. Lateman]. Moth behaviour on these plants and the importance of plant age and size in maintaining pest preference for trap crop plants were also investigated. Three times as many eggs were laid on cauliflower plants that were unprotected than on plants protected by a trap crop of white mustard. Moths remained longer on the mustard plants as a result of a doubling in the mean duration of information-providing behaviours. Plant age had little effect on P. xylostella host preference. When plant age was constant, percentage oviposition on mustard was higher when these were larger (93%) than copresented cauliflower plants, compared with when they were smaller (68%). Trap cropping with white mustard may reduce the incidence of P. xylostella in cauliflower crops. The pest management benefits of trap crops may be maximised by using trap crop plants that are larger than the main crop plants, although relatively smaller trap crop plants may still be preferred as hosts for P. xylostella per se.

Occurrence of the New Invasive Insect <I>Contarinia nasturtii</I> (Diptera: Cecidomyiidae) on Cruciferous Weeds

Contarinia nasturtii (Kieffer) (Diptera: Cecidomyiidae), a common insect pest in Europe and a new invasive pest in North America, causes severe damage to cruciferous crops. In the United States, C. nasturtii was first reported in western New York in 2004. From 2005 to 2007, field surveys were conducted in western New York to investigate the occurrence of C. nasturtii in weeds that might serve as a reservoir for this pest. The results indicate that 12 cruciferous weed species were found in and around commercial vegetable crucifer plantings, and C. nasturtii emergence was detected from most of them. The number of C. nasturtii that emerged from the weeds was low and varied by species, year, and the timing of sampling. Peak emergence from weeds in fallow fields occurred in June. Nonchoice tests in the laboratory showed that significantly fewer larvae were found on cruciferous weeds than on cauliflower plants, although C. nasturtii could lay eggs on the weeds. When weeds and cauliflower plants were simultaneously exposed to C. nasturtii adults for egg laying (choice tests), 97.3% of the C. nasturtii larvae were found on the cauliflower plants 8 d after oviposition, 2.7% on Sinapis arvensis L., and none on the other five weed species tested. Our results suggest that cruciferous weeds can serve as alternative host plants of C. nasturtii but are less suitable than cauliflower. A method of detecting C. nasturtii on weeds and control of C. nasturtii through weed management are discussed.