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1.
Charmi Shailesh Patel Janardan J. Jani Vipulkumar B. Parekh Vijay B. Darji Piyush R. Vaishnav 《Phytoparasitica》2009,37(5):407-413
India has a rich biodiversity of microbes. Soil is the major source for isolation of entomopathogens, after the infected insects
themselves. Four isolates of Helicoverpa armigera nuclear polyhedrosis virus (HearNPV) were obtained from the samples collected one each from Anand, Surat and Junagadh of
Gujarat and Patancheru of Andhra Pradesh. All the HearNPV isolates appeared as clear, irregular six-sided objects with rounded
edges, phase-bright under phase contrast. Junagadh, Surat, Patancheru and Anand isolates gave 27.47–42.80%, 36.83–51.32%,
26.05–43.76% and 42.99–54.85% mortality, respectively, when the percent mortality was pooled over period. The least number
of HearNPV polyhedral inclusion bodies (PIBs) (5.1 × 107) of the Anand isolate were required to kill 50% of the H. armigera population within 120 h. The Anand isolate was fastest (90.30 h), followed by Surat (120.26 h), Junagadh (139.53 h) and Patancheru
(143.10 h) in killing 50% of the H. armigera population at a dose of 109 PIBs ml−1. RAPD analysis of all 15 arbitrary oligonucleotide primers generated 353 scorable bands with 201 loci. A total of 181 polymorphic
bands were obtained, ranging in size from 141 to 1,873 base pairs. The percentage of polymorphic loci was 90.19%. The mean
polymorphism information content (PIC) value for 15 primers was found to be 0.99. The similarity coefficient values based
on 15 RAPD markers ranged from 0.235 to 0.407. The four isolates were grouped into two clusters: one cluster consisted of
Junagadh and Anand and the second cluster consisted of Surat and Patancheru. 相似文献
2.
The fitness cost of spinosad resistance was investigated in the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). Laboratory experiments were conducted to compare relative fitness of H. armigera between the spinosad-susceptible and -resistant strains. During the experiments, the average development periods of the resistant
strain were lengthened by 4–5 days, reflected in a prolongation of egg, larval and pupal periods. Furthermore, pupal survival,
pupal weight, the mean life span of emerged adults, eggs laid and hatched decreased greatly in the resistant strain in comparison
with the susceptible strain. Other life-cycle parameters such as larval survival, larval wet weights, prepupal periods, pupation
ratio, and sex ratio did not change significantly. As a result, both net replacement rate (R
0) and intrinsic rate of increase (r
m) were reduced for the resistant strain. Our results clearly indicated that relative fitness of resistant individuals was
reduced in the absence of spinosad. Rational measures including pesticide rotations should be expected to delay development
of resistance to spinosad in H. armigera field populations from China. 相似文献
3.
4.
为明确寄生蜂中红侧沟茧蜂Microplitis mediator与核型多角体病毒（nucleopolyhedrovirus,NPV）对寄主棉铃虫Helicoverpa armigera的联合效应,测量中红侧沟茧蜂和NPV单处理及复合处理后棉铃虫幼虫的形态学指标,并统计棉铃虫幼虫死亡率及寄生蜂中红侧沟茧蜂子代存活率。结果显示,处理3 d和5 d后,中红侧沟茧蜂和NPV单处理及复合处理的棉铃虫幼虫体长、体宽、头壳宽度、体重均显著低于对照,但各处理之间差异不显著。接入浓度为2.5×104 OBs/mL和2.5×106 OBs/mL NPV时,中红侧沟茧蜂和NPV这2种生防因子对棉铃虫均表现为拮抗效应或累加效应。接入浓度为2.5×104 OBs/mL NPV时,先寄生后接毒和先接毒后寄生处理的棉铃虫实际死亡率分别为4.35%和14.26%;接入浓度为2.5×106 OBs/mL NPV时,棉铃虫实际死亡率则分别为31.55%和94.19%,先接毒后寄生处理的棉铃虫实际死亡率均显著高于先寄生后接毒处理的实际死亡率。接入浓度为2.5×106 OBs/mL NPV时,先寄生后接毒和先接毒后寄生处理的寄生蜂子代存活率分别为54.51%和3.71%,前者显著高于后者。表明中红侧沟茧蜂寄生和NPV侵染均能显著抑制棉铃虫的生长发育,但两者联合应用时拮抗效应明显且对寄生蜂子代有影响,同时用于生物防治棉铃虫时应谨慎。 相似文献
5.
Kátia Cilene S. Felix Elineide B. Souza Sami J. Michereff Rosa L. R. Mariano 《Phytoparasitica》2012,40(1):53-62
The survival of Ralstonia solanacearum A1-9Rif race 1 phylotype I was studied in ten different soil types in the absence of the host plant as well as in infected tissues
of the stem and root of bell peppers buried in the soil at 0, 5, and 15 cm. The survival time of R. solanacearum A1-9Rif in the ten soil types ranged from 42 up to 77 days. Among the chemical and physical characteristics of the soil, clay content,
residual moisture, and available water were positively correlated, and pH was negatively correlated, with survival time, population
size at 42 days, and area under the population curve. The pathogen survival differed significantly in relation to the plant
tissues, but not with respect to the incorporation depth of the infected tissues. The root tissue of bell pepper supported
a larger bacterial population at 7 and 21 days (5 × 104 and 3.1 × 104 CFU g−1 tissue, respectively) compared with the stem tissue (0.35 × 104 and 0.48 × 104 CFU g−1 tissue, respectively) and also had a larger area under the population curve. On the other hand, the stem tissues presented
a greater decomposition rate and pH compared with the roots. In conclusion, the different types of studied soils as well as
the infected bell pepper tissues were considered potential primary sources of R. solanacearum inocula, but only for a short period. 相似文献
6.
棉铃虫核多角体病毒的生产方法及其在生物防治中的应用 总被引：4，自引：0，他引：4
本文是报道棉铃虫Heliothis armigera核多角体病毒(NPV)的生产方法及其在棉田应用的试验研究结果。NPV用棉铃虫幼虫生产。从虫卵接种开始,用人工饲料饲养棉铃虫幼虫,到四龄用病毒感染,六天后收集病死虫,病毒致死率80～85%,单虫含量4～6×10~9PIB。由棉饼粉、粗棉油等配制成诱饵加低剂量西维因作病毒增效剂与NPV混用,显著提高病毒的防治效果。四年田间试验表明,NPV杀虫剂防治棉铃虫的效果相当于或优于常用高效化学农药。1979年开展了大面积飞机微量喷雾PVN杀虫剂的试验,也取得了比较好的防治效果。 相似文献
7.
Roghayeh Hemmati Mohammad Javan-Nikkhah Celeste C. Linde 《European journal of plant pathology / European Foundation for Plant Pathology》2009,125(4):617-628
The genetic structure of 276 Sclerotinia sclerotiorum isolates representing 37 field populations from four provinces in northern Iran were analysed with six polymorphic microsatellite
loci. In total, 80 haplotypes were detected with 19 haplotypes (23.7%) shared amongst at least two regional populations. None
of the haplotypes were shared among all four regional populations. Of the 80 haplotypes, 32 haplotypes (40%) occurred in low
frequencies represented by only one isolate. Moderate levels of gene diversity (H = 0.51 to 0.61) and genotypic diversity (Ĝ = 12.0 to 22.0; clonal fraction = 0.39 to 0.67) for regional populations were observed. Genotypic diversities (Ĝ) did not differ significantly among populations. All regional populations were in linkage equilibrium indicating the occurrence
of outcrossing. Low to moderate levels of population subdivision (0.03 to 0.07), were observed among regional populations.
Only one large panmictic population was inferred by Structure, indicating no significant population structure. A Mantel test showed no significant isolation by distance (r = −0.43; P = 0.18), indicating anthropogenic movement of inoculum. The results demonstrated that S. sclerotiorum populations in northern Iran, are randomly mating and have a number of shared haplotypes among regional populations; this
possibly represents recent founder populations and/or a high occurrence of anthropogenic migration of infected plant material
among populations. 相似文献
8.
The developmental biology of Mallada desjardinsi (Navas) and Chrysoperla congrua (Walker) on the American bollworm, Helicoverpa armigera and the cotton aphid, Aphis gossypii was studied in the laboratory at 28–32°C. Total larva! periods of M. desjardinsi and C. congrua on H. armigera eggs were 14.4 and 14.8 days respectively. However, when reared on A. gossypii larval periods of M. desjardinsi and C. congrua were 14.9 and 13.5 days respectively. When reared on H. armigera 52.9% and 25% respectively of third instars of M. desjardinsis and C. congrua sp. died before pupation. However, when reared on A. gossypii 82.6% and 46.9% respectively of third instars of M. desjardinsi and C. congrua died before pupation. Thus, H. armigera eggs and A. gossypii nymphs were both adequate but not optimal diets for chrysopid larval development. The number of prey consumed by M. desjardinsi and C. congrua increased with instar. Total larval consumption of H. armigera by M. desjardinsi and C. congrua was determined to be 135.5 and 169.8 eggs respectively. However, total larval consumption of A. gossypii by M. desjardinsi and C. congrua was found to be 189.0 and 171.8 nymphs respectively. Because of its longer larval period, and higher consumption of A. gossypii, M. desjardinsi would be better suited for use against A. gossypii than C. congrua. In contrast, C. congrua whose consumption of H. armigera was higher than that of M. desjardinsi although their larval periods were similar, would appear promising for control of H. armigera. 相似文献
9.
为探索棉铃虫Helicoverpa armigera液泡型ATP酶(vacuolar-type proton ATPase,V-ATP酶)亚基A对棉铃虫生长发育的影响及其在Bt杀虫机制中的作用,采用PCR结合RACE技术克隆了棉铃虫V-ATP酶亚基A基因序列,通过实时荧光定量PCR技术测定了其在棉铃虫不同发育历期和幼虫肠道不同组织中的表达量;并比较了4龄幼虫取食含Cry1Ac蛋白饲料后中肠中该基因表达量的变化。结果显示,棉铃虫V-ATP酶亚基A基因全长2 578 bp(Gen Bank登录号KP090287),开放阅读框1 863 bp,编码621个氨基酸。V-ATP酶亚基A高度保守,不同物种间氨基酸序列同源性大于90%。V-ATP酶亚基A在棉铃虫整个生育期都有表达,在4龄幼虫体内表达量最高,是卵期的3.00倍;在幼虫肠道不同组织中,中肠中表达量最高,是后肠中的2.65倍。4龄棉铃虫幼虫取食含Cry1Ac蛋白的人工饲料后,中肠V-ATP酶亚基A的表达受到抑制,表达量为对照的0.39~0.81倍。表明V-ATP酶亚基A基因可能参与棉铃虫的生长发育和代谢过程,并可能与抵御Cry1Ac的毒杀作用有一定关系。 相似文献
10.
The functional response, development time, survival and reproduction of the lady beetle Scymnus subvillosus (Goeze) (Coleoptera: Coccinellidae) were evaluated at different densities of the mealy plum aphid Hyalopterus pruni (Geoffroy) (Homoptera: Aphididae). Treatments were carried out at 25 ± 1°C, 60 ± 10% r.h. and 16L:8D photoperiod in a controlled
temperature room. The larvae and adults of S. subvillosus were fed with different densities (5, 10, 20, 40 and 80) of H. pruni in petri dishes. The shape of the functional response was determined by logistic regression, and the values of the coefficient
of attack rates (α) and handling times (T
h) were estimated by using nonlinear least-squares regression. Behavior of each larval stage and adults matched Holling’s type
II functional response. Estimates of α for all stages of S. subvillosus tested were similar, but estimates of T
h varied; it was the shortest for adult females and the longest for third instar larva. Larvae were able to complete their
development at each of the five prey densities, but increased prey densities reduced development time and mortality rate.
Increased prey consumption did not change longevity, but resulted in a higher intrinsic rate of increase (r), the finite rate of increase (λ), net reproduction rate (R
0
), gross reproductive rates (GRR), and shorter mean generation time (T) and doubling time (DT).
This research was funded by the Yuzuncu Yil University/foundation of scientific research projects (No. 2002-ZF 044) 相似文献
11.
为明确全球气候变暖对不同寄主植物上棉铃虫Helicoverpa armigera种群发生的影响，通过收集2008—2019年全国范围、华北地区、华东地区、西北地区及华中地区7种寄主植物（小麦、玉米、大豆、棉花、花生、蔬菜和其他粮食作物）上棉铃虫成灾面积及各地区平均温度数据，采用单因素方差分析法及广义线性模型分析不同寄主植物上棉铃虫种群的发生程度。结果显示，玉米、大豆、花生和蔬菜寄主植物上棉铃虫成灾面积显著增加，棉花上棉铃虫成灾面积显著降低。玉米（全国范围、华北地区）、花生（全国范围、华中地区）及蔬菜（华东地区）上棉铃虫成灾面积随着温度距平的升高而显著增加；但棉花上棉铃虫成灾面积随着温度距平的升高而显著降低。如全国范围内，在玉米和花生上，2014—2019年棉铃虫成灾面积均显著高于2008—2013年，其增加比率分别为24.0%和34.3%；在棉花上，2014—2019年棉铃虫成灾面积显著低于2008—2013年，其降低比率为62.0%。表明全球气候变暖显著增加了玉米、花生及蔬菜上棉铃虫成灾面积，而棉花上棉铃虫成灾面积的降低主要受转Bt基因棉花种植的影响。 相似文献
12.
为明确N6-甲基腺苷（N6-methyladenosine,m6A）修饰在棉铃虫核型多角体病毒（Helicoverpa armigera nucleopolyhedrovirus,HearNPV）侵染棉铃虫中的作用,根据基因组和转录组数据,对棉铃虫m6A结合蛋白基因YTHDF1（YTH domain-containing family protein 1）进行鉴定和分析,利用实时荧光定量PCR技术检测棉铃虫YTHDF1基因的时空表达模式、HearNPV处理后的表达变化情况以及RNA干扰效率,并调查该基因下调后对HearNPV复制及感染HearNPV棉铃虫死亡情况的影响。结果显示,棉铃虫YTHDF1基因开放阅读框全长为2 019 bp,编码672个氨基酸,含有1个保守的YTH结构域,其氨基酸序列与斜纹夜蛾Spodoptera litura同源物序列一致性达87.52%。YTHDF1基因在棉铃虫不同发育阶段均有表达,其中在进入5龄期24 h幼虫中的表达量最高,在2龄取食期幼虫中的表达量最低。YTHDF1基因的空间表达谱呈现一定的组织特异性,在幼虫血细胞和成虫头部的表达量最高。HearNPV侵染棉铃虫后YTHDF1基因上调表达,经RNA干扰使该基因下调后显著抑制了HearNPV多角体蛋白基因polyhedrin的表达并延迟了感染HearNPV棉铃虫的死亡时间。表明YTHDF1基因在HearNPV侵染棉铃虫的过程中发挥着重要作用。 相似文献
13.
Isaac Y. Opoku Andrews Y. Akrofi Alex A. Appiah 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(2):167-175
Studies were conducted in two cocoa-growing areas of Ghana, one solely affected by Phytophthora palmivora and the other predominantly by Phytophthora megakarya, to determine the effectiveness of sanitation practices and fungicide application on tree trunks for the control of black
pod disease in the canopy. Sanitation practices including weeding, pruning, thinning, shade reduction and removal of mummified
pods were carried out prior to fungicide applications, and diseased pods were routinely removed at monthly intervals during
harvesting. Three types of fungicides were used: systemic (Foli-R-Fos 400) applied as injection into the main trunks, semi-systemic
(Ridomil 72 plus) and contact (Nordox 75, Kocide 101, Kocide DF, Blue Shield and Funguran-OH) applied as sprays onto pods
on the main trunk. Sanitation combined with fungicide application on the trunk significantly reduced black pod disease incidence
in the tree canopy. For fungicides applied as a spray, Ridomil 72 plus at 3.3 g l−1 and Kocide DF at 10 g l−1 and as injection, 40 ml Foli-R-Fos 400 injected twice a year, performed better than the other fungicide treatments. The position
of pods significantly influenced the incidence of canopy black pod infection in the P. megakarya predominantly affected area but to a lesser extent in the P.
palmivora solely affected area. However, no significant interactions were found between fungicide treatments and the position of pods
on the tree in both disease areas. The determined trunk-canopy relationship in the development of black pod disease on cocoa
can be used in disease control programmes to maximise the impact of sanitation practices, achieve judicious application of
fungicides, thereby reducing the environmental impact of fungicides on the cocoa ecosystem, and ultimately increase the economic
returns. 相似文献
14.
In Africa, Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae) is a key pest of cotton and vegetable crops, particularly tomato. Alternatives to insecticides to control this pest are needed such as conservation biological control. However, knowledge on the diversity and ecology of naturally occurring enemies of H. armigera is limited. A two-year field survey was conducted in a set of tomato farmer fields in the main vegetable-growing area in Senegal (Niayes) to assess the spatial and seasonal occurrence of indigenous parasitoids of H. armigera, and to evaluate the effect of insecticide use on biological control efficiency. No parasitoid emerged from H. armigera eggs. Incidence of larval parasitoids was generally moderate (20%) but highly variable (0%–100%) among fields, independently of host abundance, and negatively affected by the number of insecticide applications. Larval parasitism was largely dominated by the larval parasitoid Meteorus laphygmarum Brues (Hymenoptera, Braconidae), but a positive correlation was found between specific richness or Shannon diversity index of the parasitoid community and parasitism rate. This study is a first step toward development of research and extension programs for conservation of natural enemies in the framework of integrated management of the tomato fruitworm in Senegal. 相似文献
15.
Mumuni Abudulai Jesse Naab Shaibu Seidu Seini Israel Dzomeku Kenneth Boote Rick Brandenburg 《国际虫害防治杂志》2018,64(3):204-209
Weeds and diseases can reduce peanut (Arachis hypogaea L.) yield or increase cost of production to maintain acceptable yield. While herbicides and fungicides have limited availability in many areas of Ghana and currently are too expensive for resource-poor farmers, control by these pesticides can have a major positive impact on peanut yield. Field experiments were conducted during the rainy seasons of 2009 and 2010 in northern Ghana to determine the effects of herbicide and hand weeding in combination with fungicides on pest management and peanut yield. Peanut pod yield was often more highly correlated with disease severity and canopy defoliation resulting from early leaf spot (caused by Cercospora arachidicola Hori) and late leaf spot (caused by Cercosporidium personatum (Berk. & M.A. Curtis) Deighton) than weed biomass. In some instances, less disease and canopy defoliation were observed when weeds were not controlled effectively compared with increased weed management through hand weeding or herbicide. Two hand weedings or applying pendimethalin preemergence with one hand weeding in combination with 4 applications of triadimefon and chlorothalonil resulted in the lowest weed density and canopy defoliation and often resulted in the highest peanut yield. 相似文献
16.
Soledad Verdejo-Lucas F. Javier Sorribas 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(1):103-107
Nematode reproduction on the nematode-susceptible tomato cv. Durinta grafted onto the Mi-resistance gene tomato rootstock SC 6301 was compared to the Mi-resistance gene tomato cv. Monika in a plastic house infested with Meloidogyne javanica. The ungrafted susceptible cv. Durinta was included as a control for reference. Final soil population densities were lower
(P ≤ 0.05) on the resistant than susceptible cultivar but intermediate values were recorded on the rootstock SC 6301. The lowest
numbers of eggs per gram root were recorded on the resistant cultivar followed by those on the rootstock; in both cases, they
were lower (P < 0.05) than on the susceptible control. Cumulative yield (kilogram per square meter) was higher (P < 0.05) on the resistant than susceptible cultivar whether or not it had been grafted. The rootstock SC 6301 provided an
intermediate resistance response to M. javanica and was less effective than the resistant cultivar in suppressing nematode populations and plant damage under the experimental
conditions of this study. 相似文献
17.
Ana M. Requena M. Emilia Candela M. Emilia Requena Catalina Egea-Gilabert 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(3):511-518
The feeder roots of pepper plants (cv. California Wonder) in Campo de Cartagena (southeast Spain) were found to be severely
infected by Meloidogyne incognita. Morphometric traits, differential host test and DNA analysis based on PCR were used to characterize the nematode. Naturally
and artificially infected pepper plants showed severe yellowing and stunting, with heavily deformed and damaged root systems.
Root galls were spherical and commonly contained more than one female and egg masses with eggs. Typical giant cells with a
granular cytoplasm and many hypertrophied nuclei were observed in histological preparations. The relationship between initial
nematode population density (Pi) and pepper plant growth was tested in greenhouse experiments with inoculum levels that varied from 0 to 64 eggs and second-stage
juveniles (J2) ml−1 soil. A Seinhorst model was fitted to plant height and top fresh weight data of inoculated and non-inoculated plants. The
tolerance limit with respect to plant height and fresh top weight of pepper to M. incognita was estimated as 0.85 eggs and J2 ml−1 soil. The minimum relative values (m) for plant height and top fresh weight were 0.15 and 0.16, respectively, at Pi ≥ 64 eggs and J2 ml−1 soil. The maximum nematode reproduction rate (Pf/Pi) was 315.4 at an initial population density (Pi) of 4 eggs and J2 ml−1 soil. The obtained results could be used as a base to establish field experiments that allow strategies to prevent surpassing
the threshold of nematodes in fields that are infested. 相似文献
18.
Z. K. Punja A. Wan M. Rahman R. S. Goswami T. Barasubiye K. A. Seifert C. A. Lévesque 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(2):173-184
Fusarium equiseti is prevalent in ginseng soil, straw mulch and in ginseng root tissues and is the cause of a root surface discolouration on
ginseng grown in British Columbia. Population levels of the fungus in ginseng fields ranged from 3.8 × 103 cfu g−1 soil to 1.4 × 104 cfu g−1 soil and were highest at 0–5 cm soil depths compared to 10–15 cm. Soil population levels were negatively correlated with
S content in soil and positively correlated with Zn levels. Barley or wheat straw added to soil significantly increased population
levels under laboratory conditions. Mycelial growth in culture was highest at 26–30°C and at pH 7.2–7.8. Samples of flowers
and berries, and harvested seed, contained DNA of F. equiseti detected using a Fusarium-specific DNA array and the fungus was isolated from these tissues on agar medium. A high degree of genetic variation in the
EF-1 alpha gene sequence was present among 52 isolates of F. equiseti which originated from ginseng fields. At least seven clades were identified. Inoculum dispersal from straw mulch used in
ginseng gardens can result in seed contamination by the fungus. In addition, fungal growth near the soil surface under warm
summer conditions can result in infection and crown discolouration of ginseng roots. 相似文献
19.
Baidya N. Mahto Suraj Gurung Achala Nepal Tika B. Adhikari 《European journal of plant pathology / European Foundation for Plant Pathology》2012,133(2):405-417
Spot blotch, caused by Cochliobolus sativus (Ito & Kuribayashi) Drechs. ex Dastur, is one of the important diseases of wheat worldwide. The main objective of this study
was to investigate the phenotypic and genotypic variability among C. sativus isolates from the hills and plains in Nepal. A total of 48 monoconidial isolates of C. sativus from the hills (n = 24 isolates) and plains (n = 24 isolates) in Nepal were analyzed for morphology, aggressiveness and genetic structure. C. sativus isolates were grouped into three categories on the basis of their colony texture and mycelia colour. Thirteen isolates from
the hills and plains belonging to three morphological groups were randomly selected and evaluated for aggressiveness on eight
wheat cultivars (Chirya 1, Chirya 7, Milan/Shanghai 7, SW 89–5422, PBW 343, BL 1473, BL 3036, and RR 21) at the seedling stage.
Nonparametric analysis revealed that the isolates from the plains (median disease rating of 5) were significantly (P = 0.0001) more aggressive than the isolates from the hills (median disease rating of 3). A significant (P = 0.0001) isolate by cultivar interaction was demonstrated and the isolates from the same geographic region and morphological
group displayed different degrees of aggressiveness on wheat cultivars tested. Combined IS-PCR and rep-PCR analyses revealed
moderate gene diversity (H = 0.24 and 0.25 for the hills and plains, respectively). Low linkage disequilibrium (LD) value and non-significant (P = 0.001) population differentiation (G″ST = 0.05) were detected, indicating that isolates of C. sativus from the hills and plains in Nepal were genetically similar. Analysis of molecular variation (AMOVA) revealed low (7%) levels
of genetic variation between the hill and plain populations, whereas >93% of genetic variation was found within populations.
Overall, C. sativus isolates from Nepal are pathologically and genetically diverse, and such information will be useful in developing wheat cultivars
resistant to C. sativus. 相似文献
20.
The efficacy of three Heterorhabditis spp of entomopathogenic nematodes (EPNs) from north western Himalaya, India was studied against the larvae of pod borer, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), under the laboratory conditions. The larvae were exposed to 10, 20, 30 and 40 infective juveniles (IJs) of each nematode species for different time periods and they were found to be susceptible to all the EPNs tested. However, the susceptibility of larvae to nematode infection varied according to the concentrations of IJs and their exposure periods. The efficacy of these indigenous entomopathogenic nematodes was also compared against commercially available entomopathogenic nematode, H. indica. Appreciably good performance was achieved by H. bacteriophora (HRJ), which showed 73.3% mortality of insect larvae in 96 h exposure time against third instar larvae, while H. indica produced 80.0% mortality. However it was noticed that with the advancement of larval stage its mortality rate reduced and vice versa with the exposure period. All tested EPNs were also found to reproduce within the host and maximum production of IJs was recorded in H. bacteriophora (26.0 ± 3.76 × 103 IJs/larva) at the concentration of 40 IJs/larva. 相似文献