Low Numbers Of Larvae Research Articles

Real-time qPCR coupled with high-resolution melting curve analysis for the detection of the internal transcribed spacer 1 of Angiostrongylus costaricensis.

Abdominal angiostrongyliasis (AA) is a zoonotic and severe parasitic infection caused by Angiostrongylus costaricensis. AA is currently diagnosed by the observation of A. costaricensis-compatible structures in biopsies or the detection of antibodies in serological tests. However, molecular methods targeting homologous sequences of A. costaricensis have not been designed before, and therefore, an HRM-coupled qPCR was developed to detect the internal transcribed spacer 1 (ITS1) of the parasite. The present assay successfully amplified DNA of A. costaricensis obtained from different hosts and identified slight sequence differences through the HRM analysis. The detection limit of the HRM-qPCR was 0.00036ng/µL, 1.0ng/µL, and 0.1ng/µL when A. costaricensis DNA was diluted in nuclease-free water, whole blood, and sera, respectively, which highlights its potential use for cell-free DNA detection. Moreover, the reaction did not cross-amplify DNA of Angiostrongylus cantonensis, Strongyloides stercoralis, and other nematodes, thus emphasizing its specificity. Additionally, the assay tested positive in formalin-fixed paraffin embedded biopsies with visible A. costaricensis adults or eggs, but not in samples without evident parasites or a low number of larvae, which suggests that the reaction is useful for confirming the presence of the nematode in clinical samples. Finally, DNA of sera from patients with AA was evaluated with the HRM-qPCR but none tested positive, possibly due to long storage periods of the samples which could have led to cfDNA degradation. These results indicate that this assay may be useful in the confirmation of AA and its prospection for cell-free DNA detection protocols.

Development and Seasonal Variations of the Larvae of Three Mesopelagic Fishes near Coral Reefs in the Red Sea

This work aims to describe the larval stages and the seasonal variation in the abundance of three mesopelagic species whose larvae are surprisingly abundant near coral reef areas in the Red Sea. The larvae were collected monthly using a plankton net (500 µ) from three coastal coral reef areas surrounding Sharm El-Sheikh on the Egyptian Red Sea coast between January and December 2015. The identification of larvae was based on the morphological and meristic characteristics according to the available literature. The larvae of this species were divided into preflexion, flexion, and postflexion stages and they were also categorized according to their size into relevant size classes. Mesopelagic fishes were represented in the collection by four species belonging to four families: Vinciguerria mabahiss (Family: Phosichthyidae), Benthosema pterotum (Family: Myctophidae), Astronesthes martensii (Family: Stomiidae; subfamily: Astronesthinae), and Trichiurus sp. (Family: Trichiuridae). In general, a total of 3678 larvae were collected, of which 1191, constituting about 32% of the total fish larvae, belonged to mesopelagic species. The most abundant species was V. mabahiss, with 677 larvae that constituted 18% and 57% of the total larvae and mesopelagic fish larvae, respectively. The second most abundant species was B. pterotum, which was represented by 485 larvae (13% of the total larvae and 40% of the mesopelagic fish larvae). A. martensii was represented by the lowest number of larvae (29 larvae, 2%). Most larvae of the three species were small and in the preflexion stage, whereas larger larvae are absent. They are highly abundant in the cooler months of the year between November and April. The high number of preflexion larvae may indicate that the three mesopelagic species spawn in the colder times of the year.

No evidence for schistosome parasite fitness trade-offs in the intermediate and definitive host

BackgroundThe trematode parasite Schistosoma mansoni uses an aquatic snail intermediate and a vertebrate definitive host to complete its life cycle. We previously showed that a key transmission trait—the number of cercariae larvae shed from infected Biomphalaria spp. snails—varies significantly within and between different parasite populations and is genetically controlled by five loci. We investigated the hypothesis that the success of parasite genotypes showing high propagative fitness in the intermediate snail host may be offset by lower reproductive fitness in the definitive vertebrate host.MethodsWe investigated this trade-off hypothesis by selecting parasite progeny producing high or low number of larvae in the snail and then comparing fitness parameters and virulence in the rodent host. We infected inbred BALB/c mice using two Schistosoma mansoni parasite lines [high shedder (HS) and low shedder (LS) lines] isolated from F2 progeny generated by genetic crosses between SmLE (HS parent) and SmBRE (LS parent) parasites. We used the F3 progeny to infect two populations of inbred Biomphalaria glabrata snails. We then compared life history traits and virulence of these two selected parasite lines in the rodent host to understand pleiotropic effects of genes determining cercarial shedding in parasites infecting the definitive host.ResultsHS parasites shed high numbers of cercariae, which had a detrimental impact on snail physiology (measured by laccase-like activity and hemoglobin rate), regardless of the snail genetic background. In contrast, selected LS parasites shed fewer cercariae and had a lower impact on snail physiology. Similarly, HS worms have a higher reproductive fitness and produced more viable F3 miracidia larvae than LS parasites. This increase in transmission is correlated with an increase in virulence toward the rodent host, characterized by stronger hepato-splenomegaly and hepatic fibrosis.ConclusionsThese experiments revealed that schistosome parasite propagative and reproductive fitness was positively correlated in intermediate and definitive host (positive pleiotropy). Therefore, we rejected our trade-off hypothesis. We also showed that our selected schistosome lines exhibited low and high shedding phenotype regardless of the intermediate snail host genetic background. ​Graphical

Bio-Efficacy of Chemical Insecticides Against Defoliators Spodoptera litura and Achaea janata in Castor

Field experiments on bio-efficacy of chemical insecticides against defoliators Spodoptera litura and Achaea janata in castor was carried out at Main Oilseeds Research Station, Junagadh Agricultural University, Junagadh during consecutive three year i.e. 2015-16, 2016-17 and 2017-2018. All the treatments were significantly superior over untreated check. Results of the experiment indicated that lowest number of larvae per plant for S. litura and A. janata was recorded in the treatment of chlorantraniliprole 18.5 SC 0.006% (0.42 & 0.22 larvae/plant), which was at par with the most of the insecticidal treatments except the treatment of poneem after three days of the first spray. More or less similar trend was observed after 7 and 14 days of first spray as well as 3,7 and 14 days after second spray. The highest net return was recorded in treatment of indoxacarb 14.5 SC 0.0073% (Rs. 31870/-) followed by the treatment chlorantraniliprole 18.5 SC 0.006% (Rs. 31080/-), spinosad 45 SC 0.009% (Rs.29240/-) and emamectin benzoate 5 % WG 0.002 % (Rs. 26232/-). Looking to the ICBR, the treatment of profenophos 40 % + cypermethrin 4% 44 EC noted the highest ICBR i.e. (1:11.60) followed by the treatment of chlorpyriphos 20 EC 0.05% (1: 10.20), indoxacarb 14.5 SC 0.0073% (1:9.30) and emamectin benzoate 5 % WG 0.002 % (1:7.30).

EFFECT OF SOME BIOLOGICAL AND CHEMICAL PESTICIDES IN CONTROLLING TUTA ABSOLUTA OF TOMATO

This study was conducted at the open fields of the Agricultural Research Station in Dohuk Governorate during the year 2019 on the tomato crop, a local variety. In this study, the effect of chemical pesticides (Imidamex, Matrixine plus) and biological pesticides (Antario KAB, Biocure) were tested on the percentage of leaf infection, number of larvae, the percentage of fruit infestation and the rate of productivity of one plant. The results revealed that the lowest percentage of leaf infection and the lowest number of larvae appeared with plants treated with Biocure, with an average of 22.7% and 0.36 larva/leaf, respectively. Whereas, the lowest infection rate for fruits and the highest productivity of plants appeared of plants treated with Antariocap, as the rates were 2 fruits/plant and 7.32 kg/plant, respectively. The results showed the superiority of the Antariocap pesticide in controlling this insect, as it had the highest reduction rate in the infested tomato fruits, at a rate of 90.4%.

Evaluation of Efficacies of Some Insecticides against Major Insect Pests of Brinjal and Cabbage in Mid Hills of Meghalaya

The experiments were conducted at ICAR Research Complex for North Eastern Hill Region, Umiam, Meghalaya, India to evaluate of some insecticides against major insect pests of brinjal and cabbage under field condition. All treatments viz. indoxacarb 14.5 SC (75 and 150 g a.i. ha-1), chlorfenapyr 10 SC (100 and 200 g a.i. ha-1), chlorpyrifos 20EC (200 and 400 g a.i. ha-1) and control (water spray) were applied thrice in brinjal and twice in cabbage at 15 days intervals. Shoot infestation in brinjal was counted from randomly selected five tagged plants from each replication before spray and on 7 and 14 days after application of insecticides. Fruits infestations were counted during harvesting only. In cabbage, larval population was counted from five randomly selected tagged plants from each replication on 1 day before and on 1, 3, 7, 14 days of each spray. Results revealed that the mean shoot infestation of brinjal was lowest in indoxacarb at double the recommended dose (4.82%) followed by indoxacarb at recommended dose (6.65%) with 80.19 and 72.66% reduction respectively over control check. The lowest brinjal fruit infestation (8.25%) also recorded at double the recommended dose of indoxacarb followed recommended dose (11.48%) of same insecticide. In cabbage, pooled of two years results revealed that indoxacarb @ 150 g a.i. ha-1 was very effective treatment with lowest number of larvae (0.98 larvae plant-1) followed by indoxacarb @ 75 g a.i. ha-1 (2.21 larvae plant-1) with higher marketable yield at both these treatments.

Potential use of entomopathogenic nematodes against the soil dwelling stages of onion thrips, Thrips tabaci Lindeman: Laboratory, greenhouse and field trials

Onion thrips Thrips tabaci Lindeman (Thysanoptera: Thripidae) is one of the most damaging insect pests of onion Allium cepa L., which is an economically important agriculture crop cultivated worldwide. This is first comprehensive study in which we have tested a broad range of entomopathogenic nematodes (EPN) species against different developmental stages of T. tabaci in laboratory, greenhouse and field trials. We performed several bioassays to assess the efficacy of different species of EPNs against different soil inhabiting stages of T. tabaci under various conditions. In screening bioassays, at 100 infective juveniles (IJs) cm−2 mortality ranged from 8.5 to 74.2% and 5.0–62.7% among all the tested EPNs (Steinernema carpocapsae (ALL strain), S. glaseri (NC), S. riobrave (355), S. feltiae (SN strain), S. rarum (17 C&E), Heterorhabditis bacteriophora (VS), H. georgiana (Kesha), H. indica (HOM1), H. floridensis (K22) and H. megidis (UK211 strain)) in prepupae and pupae, respectively. Five EPNs species (H. bacteriophora, S. feltiae, S. carpocapsae, S. riobrave and H. indica) selected from the screening bioassay were further evaluated against prepupae, pupae and late second instar larvae at four different concentrations i.e. 50, 100, 150 and 200 IJs cm−2. A clear dose response relationship was observed among all the tested species against all the developmental stages. The prepupal stage was the most susceptible (87.9% mortality) followed by pupae (78.1% mortality) and late second instar larvae (59.4% mortality) when exposed to H. bacteriophora at highest dose tested (200 IJs cm−2). Among the different temperatures tested, maximum efficacy was observed by all the tested EPNs at 25 °C and 30 °C followed by 35 °C and 20 °C with H. bacteriophora and S. feltiae being most virulent among all species at all the tested temperatures. In a potted soil bioassay, the lowest adult emergences were observed in the H. bacteriophora treatment for both prepupae and pupae. In potted plant bioassay under the greenhouse condition, significant lower number of adult emergence was observed among H. bacteriophora as compare to control group. Under field conditions, the lowest number of larvae (4.9 per plant in 2017–18 and 9.6 per plant in 2018–19) and adult (0.1 per plant in 2017–18 and 5.2 per plant in 2018–19) were observed in H. bacteriophora treated plots compared to control larvae (29.4 per plant in 2017–18 and 44.1 per plant in 2018–19) and adults (20.0 per plant in 2017–18 and 28.1 in 2018–19). Our results revealed that EPNs could be included in integrated pest management programs for T. tabaci in onion production systems.

Inheritance of Antibiosis Resistance to the Dectes Stem Borer, Dectes texanus, in Soybean PI165673

Dectes texanus larvae girdles the stems of soybean and cultivated sunflowers causing significant yield losses in North America. The soybean Plant Introduction (PI) 165673 exhibits antibiosis resistance to the larval stage. The objectives of this study were: (1) to determine the inheritance of D. texanus resistance in PI165673; (2) evaluate PI165673 antibiosis resistance before 21 d post infestation; (3) evaluate girdling damage in PI16563 at the end of the season. K07-1544/PI165673 F2 and F2:3 populations were tested for resistance to D. texanus in 2011 and 2012, and PI165673 antibiosis resistance and girdling damage were evaluated in 2014. Segregation for resistance to D. texanus and heritability estimates in the F2 and F2:3 populations indicated that resistance was controlled by two genes with dominant and recessive epistasis. Antibiosis evaluations indicated: (1) PI165673 contained lower number of larvae and eggs relative to the number of oviposition punctures at 15 d post infestation; (2) the proportion of first-instar larvae was higher in PI165673 at 15 d post infestation; (3) larvae reach the sixth-instar stage in PI165673. None of the PI165673 plants were girdled at the end of the season. Identification of additional sources of D. texanus resistance is required to impair larval development in the stem.

SERANGAN HAMA PENGGEREK POLONG PADA ENAM VARIETAS KEDELAI DAN PENGARUHNYA TERHADAP HASIL

[POD BORER ATTACK ON SIX SOYBEAN VARIETIES AND THEIR EFFECTS ON YIELD]. This study aims to determine the level of pod borer attack on six soybean varieties and their effects on yields. This research was conducted from December 2017 to March 2018 in the Experimental Field of the Faculty of Agriculture, University of Bengkulu, Kandang Limun Village, Muara Bangkahulu District, Bengkulu City. The experimental design used was a Randomized Complete Block Design (RCBD) with the treatment of six soybean varieties (Demas, Argomulyo, Dega, Ringing, Echo, and Dena I) and was repeated 4 times so that there were 24 experimental units. The results showed that the percentage of pod attack on the Demas, Argomulyo, Ringing, Gema, and Dena I varieties was classified as resistant, while the Dega variety was relatively resistant. Whereas the percentage of seed attack in all soybean varieties tested was classified as resistant. Argomulyo varieties have higher resistance to pod borer attack than other varieties because they produce the highest number of trichomes, and the lowest number of larvae per plant. Argomulyo variety produces the highest number of seed weight per plant, and the highest seed weight per plot. The echo variety produces the highest number of total pods, while the Dega variety produces the highest weight of 100 seeds.

Evaluation of the chemical composition and bioactivity of essential oils from Cinnamomum camphora (L.) J.Presl. (Lauraceae), Piper nigrum L. (Piperaceae) and Stemona japonica (Miq.) (Stemonaceae) against Oryzaephilus surinamensis (Linnaeus, 1758) (Coleoptera: Silvanidae)

Abstract Oryzaephilus surinamensis is a serious insect pest of many stored products. Repellency and fumigation tests were performed to manage it. Essential oils (EO) from three plants – Cinnamomum camphora, Piper nigrum and Stemona japonica – were tested on Oryzaephilus surinamensis in the laboratory. Repellency was tested on filter paper in Petri dishes at a concentration of 31.4 μg/cm2, and 20 adults (10 days old) were observed for repellency behaviour 12, 24, 48 and 96 hours after the bioassay without any food. Cinnamomum camphora EO was the strongest repellent (83.75 ± 1.83%), followed by the Piper nigrum and Stemona japonica EOs. The eggs were obtained by maintaining 20 individuals (males and females) for 24 h in a 100 mL glass jar containing 5 g of diet feed. To evaluate the effect of EO on the development of larvae and adults, a filter paper disc impregnated with 0.1 mL of EO was placed on the inner side of the lid of the jar containing the eggs and diet feed. After 40 days, the number of adults and larvae in the jar was counted. All three EOs exhibited bioactivity against the development of larvae and adults. A relatively low number of larvae and adults was recorded in Cinnamomum camphora, followed by Stemona japonica and Piper nigrum. Gas chromatography/mass spectrometry was used to identify the major compounds in the EOs. Further studies are recommended to evaluate their bioactivity against different insect pests in stored seeds.

Management of brinjal shoot and fruit borer using selected botanicals

The study was conducted to evaluate the effect of botanicals namely neem leaf extract, neem oil, mahogany oil, mahogany oil + mahogany cake, garlic extract, tobacco leaf extract along with an untreated control to manage brinjal shoot and fruit borer (BSFB). The percent shoot infestation reduction over control was the highest in mahogany oil + mahogany cake treated plot resulting 62.39%, 64.44%, 67.86% and 71.05% reduction at vegetative stage and early, mid and late fruiting stage, respectively. The same treatment provided the highest fruit infestation reduction over control resulting 86.70%, 85.08% and 85.50% reduction at early, mid and late fruiting stage, respectively. The lowest number of larvae per infested shoot was recorded 1.10 and 1.08 in the same treatment at early and mid fruiting stage, respectively but notat vegetative stage and late fruiting stages. The number of larvae per infested fruit was similarly lowest having 1.50, 1.06 and 1.07 at early, mid and late fruiting stage, respectively using the same approach. The maximum yield (35.82 t ha-1) was achieved in the mahogany oil + mahogany cake treated plot with the highest benefit cost ratio (2.35).Bangladesh J. Agril. Res. 43(3): 431-440, September 2018

Evaluation of nine genotypes of oilseed rape (Brassica napus L.) for larval infestation and performance of rape stem weevil (Ceutorhynchus napi Gyll.).

The rape stem weevil, Ceutorhynchus napi Gyll., is a serious pest of winter oilseed rape (Brassica napus L.) crops in Europe causing severe yield loss. In currently used oilseed rape cultivars no resistance to C. napi has been identified. Resynthesized lines of B. napus have potential to broaden the genetic variability and may improve resistance to insect pests. In this study, the susceptibility to C. napi of three cultivars, one breeding line and five resynthesized lines of oilseed rape was compared in a semi-field plot experiment under multi-choice conditions. Plant acceptance for oviposition was estimated by counting the number of C. napi larvae in stems. The larval instar index and the dry body mass were assessed as indicators of larval performance. The extent of larval feeding within stems was determined by the stem injury coefficient. Morphological stem traits and stem contents of glucosinolates were assessed as potential mediators of resistance. The resynthesized line S30 had significantly fewer larvae than the cultivars Express617 and Visby and the resynthesized lines L122 and L16. The low level of larval infestation in S30 was associated with a low larval instar and stem injury index. Low numbers of larvae were not correlated with the length or diameter of stems, and the level of stem glucosinolates. As indicated by the low larval infestation and slow larval development the resistance of S30 to C. napi is based on both antixenotic and antibiotic properties of the genotypes. The resynthesized line S30 should therefore be introduced into B. napus breeding programs to enhance resistance against C. napi.

Field evaluation of three biopesticides for control of the raspberry cane midge, Resseliella thobaldi (Barnes) in Bulgaria

The raspberry cane midge, Resseliella theobaldi is a key pest on red raspberry, Rubus idaeus. The larvae of the insect severely attack the raspberry canes, resulting in premature death of the plant canes. In the last decade, organic production of raspberry fruits has significantly increased in Bulgaria. At the same time there are few products of botanical or microbiological origin that might be used for control of this pest. In present study the effect of NeemAzal® T/C (azadirachtin A), Sineis 480 SC® (spinosad), and Bacillus subtilis on R. theobaldi was evaluated. The experiments were conducted in two raspberry fields at different altitude. In the field at lower altitude (196 m), the raspberry cane midge has developed four generation per year, while in the field at higher altitude (960 m) three generations of the pest have been completed. Lowest number of larvae in raspberry canes was observed after application of NeemAzal® T/C, and B. subtilis in both raspberry fields. Both products demonstrated highest efficacy at 7th day after treatment, when the number of larvae per splits was 67.1-82.5% for NeemAzal® T/C, and 75.1-81.2% for B. subtilis lower compared with the control at the two experimental sites.

Polyphagy in an uncertain environment: Helicoverpa punctigera in inland Australia

We investigated potential primary hosts for Helicoverpa punctigera, a polyphagous lepidopteran pest which affects many crops, but also has many native hosts in non-cropping regions of inland Australia. The most common hosts are Asteraceae and Fabaceae, but there is little information on the relative importance of different species in these families for the population dynamics of H. punctigera in the inland. We tested three common hosts, one legume (Cullen cinereum) and two daisies, Rhodanthe floribunda and Polycalymma stuartii, for their suitability for survival and growth of early instar larvae. Survival was high on the flowers of all three species, and on the leaves of C. cinereum and R. floribunda, but low on leaves of P. stuartii. There were significant differences in growth rates, measured by head widths, in the order of C. cinereum > R. floribunda > P. stuartii, and flowers > leaves. They were strongly correlated with nitrogen content, measured by fresh weight. Field surveys of larval populations in western Queensland indicated that two legume species, C. cinereum and Cullen pallidum, were widely utilized and supported many larvae. Daisies were generally less widely used and/or had lower numbers of larvae. When C. cinereum or C. pallidum was found near daisies, the legume had more larvae if both the daisy and the legume were flowering, but this was reversed if only the daisy was flowering. The seasonality and habitats of the daisies and legumes are different. C. cinereum and C. pallidum (a new host record for H. punctigera) may be primary hosts of H. punctigera in inland Australia and key hosts for maintaining populations in flood plains. However the areas occupied by daisies can be more extensive depending on rainfall, and some species may be critical in generating outbreaks that affect cropping areas in southeast Australia.

Efficacy of novel insecticides against pod borer,Helicoverpa armigera(Hubner) in vegetable pea

A field experiment was conducted to determine the comparative efficacy of insecticides, i.e., lambda cyhalothrin 5 EC @ 500 ml/ha, carbosulfan 25 EC @ 1000 ml/ha, indoxacarb 14.5 SC @ 500 ml/ha, bifenthrin 20 EC @ 500 ml/ha, novaluron 10 EC @ 750 ml/ha, flubendiamide 39.35 EC @ 75 ml/ha, spinosad 45 SC @ 500 ml/ha and cypermethrin 20 EC @ 1000 ml/ha biopesticide, viz., B t @ 1.5 kg/ha and botanical, viz., Neemarin 1500 ppm @ 3000 ml/ha, which were sprayed on vegetable pea variety arkel against pod borer, Helicoverpa armigera (Hubner) during rabi season of year 2010–11 and 2011–12. The effect of these applications was also recorded on the yield attributes. All the treatments had the comparable lower number of larvae as well as pod and seed infestation than un-treated control. Flubendiamide was best with lowest pod and seed infestation of 10.73 and 12.59 per cent, respectively and 95.84 q/ha yield followed by indoxacarb, spinosad, novaluron, carbosulfan, bifenthrin, lambda cyhalothrin, cypermethrin, neemarin and Bt, which gave 93.56, 91.63, 89.74, 83.22, 81.52, 79.42, 75.97, 72.78 and 68.99 q/ha yield, respectively.

Efficacy of novel insecticides against POD borer,Helicoverpa Armigera(HUBNER) in Chickpea

A field experiment was conducted to determine the comparative efficacy of insecticides i.e. lambda cyhalothrin 5 EC @ 500 ml/ha, carbosulfan 25 EC @ 1000 ml/ha, indoxacarb 14.5 SC @ 500 ml/ha, bifenthrin 20 EC @ 500 ml/ha, novaluron 10 EC @ 750 ml/ha, flubendiamide 39.35 EC @ 75 ml/ha, spinosad 45 SC @ 500 ml/ha and cypermethrin 25 EC @ 1250 ml/ha biopesticide viz., B t @ 1.5 kg/ha and botanical viz., Neemarin 1500 ppm @ 3000 ml/ha, which were sprayed on chickpea variety surya against pod borer, Helicoverpa armigera (Hubner) during rabi 2011–12 and 2012–13. The effect of these applications was also recorded on the yield attributes. All the treatments had the comparable lower number of larvae as well as pod infestation than untreated control. Flubendiamide was best with lowest pod infestation of 10.73 and 12.59%, respectively and 16.84 q/ha yield followed by indoxacarb, spinosad, novaluron, carbosulfan, bifenthrin, lambda cyhalothrin, cypermethrin, neemarin and Bt.

Ovipositional Preference and Larval Performance of the Banded Sunflower Moth (Lepidoptera: Tortricidae) and Its Larval Parasitoids on Resistant and Susceptible Lines of Sunflower (Asterales: Asteraceae)

Banded sunflower moth, Cochylis hospes Walsingham, is one of the most destructive seed-feeding insect pests of sunflowers, causing significant economic yield losses in the northern Great Plains. In an attempt to understand host-plant resistance mechanisms for this pest, we field-tested, over several years, the effects of seven sunflower accessions, rated as resistant to C. hospes in previous screening trials, and a susceptible control (Par 1673-2), on the ovipositional preference and larval performance of C. hospes and its larval parasitoids. Of the resistant accessions, PI 494859 was the most preferred for oviposition, receiving a significantly greater number of eggs per head than did the susceptible Par 1673-2 in 2 of 3 yr. However, the numbers of larvae, and consequently the rate of seed infestation, found in PI 494859 heads were significantly lower than those in Par 1673-2 heads over all 3 yr. Female moths laid relatively few eggs on accessions PI 170385, 291403, and 251902, compared with on Par 1673-2, resulting in lower numbers of larvae per head and lower percentages of seed damaged. No association was observed between the concentrations of two diterpenoid alcohols or two diterpenoid acids in sunflower bracts and the numbers of eggs laid on the heads of the accessions. The number of banded sunflower moth larvae and the proportion of seeds damaged were positively correlated with kaurenoic acid concentrations and negatively correlated with kauranol concentrations. A positive association between resistance to larval feeding and parasitism was found in years 2006 and 2008, with resistant accessions having significantly greater proportions of parasitized larvae than did the susceptible Par 1673-2.

Seasonal population fluctuations of the diamondback moth, Plutella xylostella (L.) (Lep.: Plutellidae) on different cauliflower cultivars

The diamondback moth, Plutella xylostella (L.) (Lep.: Plutellidae) is one of the most important pests of cruciferous plants throughout the world. In recent years, it has been identified as a serious pest of the cauliflower fields in Tehran province. Resistance of P. xylostella to all main groups of insecticides has been recorded and it is ranked in the 20 most resistant pest species reported until now. According to many researchers, to solve the problem of pest resistance to chemical pesticides, an integrated pest management programme should be used. Despite this condition, it seems that the use of resistant cauliflower cultivars is an appropriate policy for integrated control of the pest in the field. In order to identify the most resistant cultivar in the field, eight cauliflower cultivars in a completely randomised design with five replicates were planted at the Shahed University research field (south of Tehran). Density of eggs, larvae and pupae of P. xylostella were measured every 10 days in these cultivars. The results showed that there is no significant difference between numbers of eggs per plant on different cultivars. But number of larvae and pupae per plant were significantly different among different cultivars. Smilla and Snow mystique cultivars had the highest number of larvae and pupae. On the other hand, Buris and Snow crown cultivars had the lowest number of pupae and Snow crown and SG cultivars had the lowest number of larvae per plant. According to the results, the Buris and Snow crown cultivars had the lowest infestation and had a kind of resistance to pest.

Arbuscular mycorrhizal fungi mediate below‐ground plant–herbivore interactions: a phylogenetic study

Summary Ecological interactions are complex networks, but have typically been studied in a pairwise fashion. Examining how third‐party species can modify the outcome of pairwise interactions may allow us to better predict their outcomes in realistic systems. For instance, arbuscular mycorrhizal fungi (AMF) can affect plant interactions with other organisms, including below‐ground herbivores, but the mechanisms underlying these effects remain unclear. Here, we use a comparative, phylogenetically controlled approach to test the relative importance of mycorrhizal colonization and plant chemical defences (cardenolides) in predicting plant survival and the abundance of a generalist below‐ground herbivore across 14 species of milkweeds (Asclepias spp.). Plants were inoculated with a mixture of four generalist AMF species or left uninoculated. After 1 month, larvae of Bradysia sp. (Diptera: Sciaridae), a generalist below‐ground herbivore, colonized plant roots. We performed phylogenetically controlled analyses to assess the influence of AMF colonization and toxic cardenolides on plant growth, mortality and infestation by fungus gnats. Overall, plants inoculated with AMF exhibited greater survival than did uninoculated plants. Additionally, surviving inoculated plants had lower numbers of larvae in their roots and fewer non‐AM fungi than surviving uninoculated plants. In phylogenetic controlled regressions, gnat density in roots was better predicted by the extent of root colonized by AMF than by root cardenolide concentration. Taken as a whole, AMF modify the effect of below‐ground herbivores on plants in a species‐specific manner, independent of changes in chemical defence. This study adds to the growing body of literature demonstrating that mycorrhizal fungi may improve plant fitness by conferring protection against antagonists, rather than growth benefits. In addition, we advocate using comparative analyses to disentangle the roles of shared history and ecology in shaping trait expression and to better predict the outcomes of complex multitrophic interactions.

COMPARISON OF THREE DIFFERENT TECHNIQUES OF GENE TRANSFER IN HUMPBACK GROUPER ( ) CROMILEPTES ALTIVELIS

Humpback grouper is one of the most cultured fishes in Asia, including Indonesia. Themain problemfaced by humpback culture is its slow growth rate.One of themethods that willbe more effective and efficient to solve the problem is using transgenic technique. This studywas conducted to determine the effectiveness of transfection,microinjection and electroporationtechniques on gene transfer in humpback grouper. transfection was performed byincubating sperm to the foreign DNA (pktBP-ktGH gene construct)-transfectant complexsolution, while was by injecting those complex solution into testis of mature males.Microinjection was conducted in 2-4 cell stage embryos using 25 μg/ml of foreign DNAsolution, and duration of injection was 1, 2 and 3 seconds. Electroporation by 50 V, 30 ms ofpulse length, 5 of pulse number and 0.1 of pulse interval was performed to sperm using threeDNA concentration of 5, 10 and 20 μg/ml. The incorporation of foreign DNA in sperm andembryos were analyzed using PCR method. Based on PCR analysis, an optimum DNAconcentration for electroporation was 10 μg/ml. Limited number of embryos could bemicroinjected during 20-30 min to reach 2-4 cell stage. Microinjection for 1 second showedhigher survival rate of embryos, although none or very low number of larvae was hatched.Transfast was an effective DNA delivery reagent for humpback grouper sperm. Foreign DNAcould be detected in sperm from two out of ten transfected fish at least 36 hours posttransfection (hpt). By transfection, foreign DNA was detected in sperm at 48 hpt 25 Cincubation temperature. Our study revealed that transfection, microinjection as well aselectroporation could be used as transgenesis methods in humpback grouper. By means ofsimplicity and efficacy, however, electroporationwas an appropriate gene transfermethod.oIn vitroin vivoin vivoin vitro