Dysdercus Koenigii Research Articles

The Development of Antilochus coquebertii Fabr. (Heteroptera: Pyrrhocoridae) on Different Artificial Diets

Antilochus coquebertii Fabr is an important predator of the red cotton stainer (Dysdercus koenigii) in agricultural crops. The present study explores the development of A. coquebertii reared on three different artificial diets to enhance the efficiency of development and commercial production of this predator. Three artificial diets were prepared from the essential ingredients necessary for the insect's development and reproduction and tested under controlled conditions. The results showed that of all diet ingredients; both chicken liver and Nestle® bonyad provided a rich source of vitamin E, and efficiently supported the insect's fecundity and survival. The solid chicken liver (SCL) diet No. 3 showed good adult survival while adult longevity was enhanced with diet No. 2 containing chicken liver paste (CLP). Collectively, both diets, No. 2 (CLP) and No. 3 (SCL) were significantly effective in promoting the predator's development. The development of artificial diet can play an important role in sustaining the whole life cycle of A. coquebertii and allow the commercial production of this predator in the absence of its natural prey for biological control of D. keonigii as well as for research and development.

Effects of hexane extract of Lantana camara leaves on reproductive bioactivities of Dysdercus koenigii Fabricius (Heteroptera: Pyrrhocoreidae)

Effects of hexane extract of Lantana camara leaves were investigated on reproductive bioactivities of Dysdercus koenigii by assessing mating behavior, oviposition behavior and fertility of the adults emerged from treated fifth instar nymphs. Leaves of L. camara were extracted in hexane by ‘cold extraction method’. The fifth instar nymphs were treated with the extract by ‘dry film residual method’ for 24 h and the adults emerged from these nymphs were used for the experiments. The results indicated that treated males showed altered courtship behaviour, lesser number of mounting attempts and took relatively more time to mate than the normal males. The treated females, very often, exhibited mating refusal and non-receptive behaviour towards the courting males. This led to decrease in percent successful mating. Also, the mating in the treated insects frequently got disrupted and terminated prior to insemination. The treatment of the females with the extract resulted in alteration of their oviposition behaviour. Consequently, the treated females laid lesser number of egg batches and total number of eggs in their life span. Although the eggs laid by the treated females were fertile, the percent hatchability was lesser than normal. The results signify that hexane leaf extract of L. camara possesses phytochemicals, which adversely impaired the reproductive bioactivities of D. koenigii. Therefore, some of these compounds individually or synergistically can be employed in integrated pest management of D. koenigii by hampering its reproductive potential.

Evaluation of <i>Aspergillus niger</i> as a Biocontrol Agent in the Insect Pest Management of Red Cotton Bug, <i>Dysdercus koenigii</i> (Heteroptera: Pyrrhocoridae)

The present work evaluates the efficacy of Aspergillus niger as a biocontrol agent against Dysdercus koenigii. Three concentrations (C1:1 × 104, C2:1 × 105 and C3:1 × 106 spores/mL respectively) were applied topically to the arthrodial membrane of adult insects and virulence of the fungi in terms of mortality was obtained, which was highest (66.66%) after 96 h post infection with 1 × 106 spores/mL. Its effect on cellular immune response was investigated. The decline in hemocyte count was highest in C3 group treated, i.e. 6992.66±216.34, followed by other groups. Differential hemocyte counts showed that granulocytes and plasmatocytes were the most affected hemocytes with count 26.33±0.66, 24±1.15 respectively in “C3” treated group in comparison to control, 33.66±2.07, 39.66±0.88 respectively. The humoral response was also studied by assessing the activity of four important antioxidant enzymes (superoxide dismutase, catalase, cytochrome p450 and glutathione-S-transferase) and lipid peroxidation that showed significant changes. Based on mortality test we can say that even the sub-lethal concentration can pose significant threat on insect pest. Our results further revealed that Aspergillus niger compromises the immunological parameters of insects and help us understand the underlying mechanism of insect response towards pathogens.

Relevance of prolonged first mating in reproductive bioactivities of Dysdercus koenigii (Fabricius, 1775) (Heteroptera: Pyrrhocoridae)

Abstract Adults of Dysdercus koenigii remain in continuous copula for up to 72h. The adaptive significance of prolonged copulation in the reproductive bioactivities of D. koenigii was investigated by a series of interrupted mating experiments. The adults were allowed to mate for a specified duration, after which mating was forcibly terminated. The study indicated that insemination in the female takes place during the first day of mating. This was reflected by the observation that 24h mated females laid fertile eggs. Prolonged mating modifies the female’s reproductive behaviour. The duration of mating had a profound effect on the onset of oviposition as well as the total number of eggs and egg batches laid by a female during her lifetime. Female fertility was also correlated with the duration of mating. Therefore, a female mated for 24h laid fewer fertile eggs in comparison to females mated for 48h or 72h. Hatching success decreased significantly in the egg batches laid by a female during the latter part of her life. A mated female exhibited rhythmic ovipositional behaviour. Our results indicated that the rhythmicity of the oviposition changed as a consequence of the different duration of mating. For instance, in females mated for 24h, there was a change in the number of eggs laid and in the rhythmicity of ovipositional peaks. Further, the rate of oocyte growth appeared to be enhanced by mating. This was evidenced by the shorter inter-oviposition period in the case of females mated for a longer period. It is suggested that throughout mating, females acquire additional sperm and non-gametic resources, such as male accessory gland secretions, which govern their reproductive behaviour and physiology.

Effects of Ocimum sanctum hexane extract on survival and development of Dysdercus koenigii Fabricius (Heteroptera: Pyrrhocoriedae)

The effects of hexane extract of Ocimum sanctum leaves on the survival, longevity, growth and development of the Dysdercus koenigii Fabricius were investigated. Newly emerged fifth instar nymphs were exposed to nine concentrations ranging from 0.00625% to 10% of the extract for 24 h by “dry film residual method.” The results indicated that the extract has adverse effect on various life activities studied. The effects were dose related; exposure to a dose of 5% or more causes high mortality. Normal adults were not produced from the nymphs treated with extract concentrations of 1.25% or more. The treated nymphs exhibited developmental malformation. The gas chromatography and mass spectroscopy analysis of the extract revealed presence of chemical compounds having insecticidal and juvenile hormone (JH) mimicking activities. Some of the compounds act as precursors of JH biosynthetic pathways. Therefore, these compounds may individually or synergistically can be used in management of D. koenigii and other insect pests.

Field evolved resistance to pyrethroids, neonicotinoids and biopesticides in Dysdercus koenigii (Hemiptera: Pyrrhocoridae) from Punjab, Pakistan

The red cotton bug, Dysdercus koenigii (Fabricius) is an important emerging economic pest of cotton, Gossypium hirsutum Linnaeus in Pakistan. Insecticides are the primary management tactics to suppress populations of this pest. However, resistance to insecticides evolves due to substantial and repeated applications. The resistance to pyrethroids, neonicotinoids and biopesticides have been evaluated in many pests worldwide, nevertheless lack of information in D. koenigii. Therefore, the aforementioned insecticide resistance in five field populations of D. koenigii collected from Multan, Makhdoom Rashid, Jahanian, Lodhran and Vehari districts of Punjab, Pakistan during 2015–2017 was determined by using seed dip method. Based on the present results, D. koenigii has developed moderate to very high resistance to acetamiprid (RR = 33–433) and imidacloprid (RR = 21–173), low to high resistance to emamectin benzoate (RR = 14–52), and very low to high resistance to spinosad (RR = 4.13–54), compared to the susceptible population. However, all field populations of D. koenigii remained susceptible to deltamethrin (RR = 0.62–2.17) and lambda-cyhalothrin (RR = 0.91–1.97). A rotational use of pyrethroids with provision of other integrated pest management tactics is recommended to manage insecticide resistance in D. koenigii.

Effects of selected synthetic insecticides on the total and differential populations of circulating haemocytes in adults of the red cotton stainer bug Dysdercus koenigii (Fabricius) (Hemiptera: Pyrrhocoridae).

Red cotton bug, Dysdercus koenigii (Hemiptera: Pyrrhocoridae), has become the major insect pest of various crops, including cotton, and thereby reducing the yield qualitatively and quantitatively and synthetic insecticides belonging to different groups are the major control agents for such insect pests. A laboratory experiment was carried out to evaluate the effect of different conventional insecticides, i.e., imidacloprid, deltamethrin, lambda cyhalothrin, gamma cyhalothrin and cyfluthirn on haemocytes of D. koenigii. The individuals were exposed to insecticides separately and data was recorded after 30 and 60min of the exposure. The findings of current study depicted chlorpyrifos to be more effective and significant alterations in total haemocyte counts and differential haemocyte counts were observed in the cyfluthirn treated D. koenigii. In addition to this, cell structure was also disrupted as an immune response. Similar studies would also be helpful to understand the defence mechanisms of insects against the xenobiotics which will help to device efficient management tools for D. koenigii.

Impact of Lantana camara hexane extract on survival, growth and development of Dysdercus koenigii Fabricius (Heteroptera: Pyrrhocoriedae)

Present research work investigated the impact of hexane extract of Lantana camara leaves on the survival, survival duration, growth and development of the Dysdercus koenigii. Newly emerged fifth instar nymphs were exposed to nine concentrations viz. 10%, 5%, 2.5%, 1.25% 0.1%, 0.05%, 0.025%, 0.0125% and 0.00625% of the extract by ‘dry film residual method’ for 24h. The results indicated that the survival and the growth of the nymphs decreased with increasing concentrations of the L. camara extract. The nymphs presented developmental malformation including incomplete moulting followed by death of the moulting nymphs, supernumerary nymphal instars, adults with wing deformities, and adults with exuviae attached to the body. The GC–MS analysis of the extract indicated presence of phytoconstituents with insecticidal activities, and intermediates of the juvenile hormone biosynthetic pathway. It was surmised that these intermediates individually or synergistically influence JH biosynthesis. L. camara extract causes mortality, inhibits growth and development and results in developmental anomalies in the D. koenigii thus indicated its potentials in the ‘integrated pest management’.

Life traits and predatory potential of Antilochus coqueberti (Fab.) (Heteroptera: Pyrrhocoridae) against Dysdercus koenigii Fab.

The red cotton bug, Dysdercus koenigii Fab., and its specialized predator Antilochus coquebertii (Fab.), are among the most abundant insects in Asian cotton agro-ecosystems. To gauge the potential of using A. coquebertii to control D. koenigii in cotton, we tested the role of feeding on cotton leaves in development of the predator, prey stage preference and characterized the functional response of the predator to prey density under laboratory conditions. Antilochus coquebertii exhibited an active hunting strategy indicative of using both olfactory and visual orientation. Immature stages of the predator successfully developed and reproduced when offered D. koenigii or cotton leaves with D. koenigii. However, A. coquebertii nymphs failed to develop past the third instar when feeding on cotton leaves alone. The food regime did not significantly affect body size of the predator. Mated male and female adults live long when fed with D. koenigii. Total number of prey consumed by an adult predator during 15-days observation reveals not much deviation when offered D. koenigii or cotton leaves with D. koenigii. The adults of A. coquebertii killed a maximum of six D. koenigii adults per day, and were preying on D. koenigii populations in a density dependent manner (showed a type II functional response). We argue that A. coquebertii has considerable potential for the biological control of the red cotton bug D. koenigii.

Hemipteroseius vikrami Menon: a junior synonym of H. indicus (Krantz & Khot) (Acari: Otopheidomenidae) with comments on the sigilla of the dorsal shield

Hemipteroseius vikrami Menon, 2011 (Acari: Otopheidomenidae: Treatinae) has been considered a junior synonym of Hemipteroseius indicus (Krantz & Khot, 1962). Both species were described from India from the red cotton bugs Dysdercus koenigii (F.) and Dysdercus cingulatus (F.), the latter is widely distributed in India and some other countries. The sigilla of the podonotum and opisthonotum are also described for the first time in this mite.

Impact of Dysdercus koenigii Fabricius (Hemiptera: Pyrrhcoridae) density-dependent population on agronomic and qualitative characteristics of different transgenic cotton varieties

The cotton stainer, Dysdercus koenigii Fabricius (Hemiptera: Pyrrhcoridae), has become a major threat to transgenic cotton as it causes warts on the internal carpel wall of cotton boll, severe lint staining, lint locks, and lint lesions. Thus, keeping in view the importance of this pest on cotton, in the present study, screening of 13 transgenic cotton genotypes was performed and the population of D. koenigii was determined on these genotypes during 2012–13. Furthermore, among these genotypes, a high yielding advanced cultivar (FH-114) was selected for further experiments. A number of five different densities of D. koenigii (5, 10, 15, 20, and 25) at adult stage with well-developed proboscis were released in the cages along with a control treatment. Cotton genotypes FH-312, FH-2073, FH-Lalazar, FH-142, and MNH-886 possessed minimum population (1.33 D. koenigii per plant) compared to FH-324 and FH-444 (6.0 D. koenigii per plant). The number of bolls per plant and boll weight decreased as a result of increased densities. The increased density of D. koenigii resulted in fewer bolls per plant (12.1 bolls), reduced boll weight (2.1 g), germination (39.1%), ginning out turn (38.3%), staple length (27.8 mm), and staple fineness (4.0 μg/in.) when compared with un-infested plants (30.6, 3.2 g, 77.3%, 41.5%, 28.8 mm, and 4.4 μg/in.), respectively. Correlation analysis revealed that bolls per plant, boll weight, germination, ginning out turn, and staple fineness resulted in negative and significant correlation with density of D. koenigii with r-values of −0.95, −0.98, −0.98, −0.8, and −0.85, respectively. Coefficient of determination (R2) demonstrated that bolls per plant, boll weight, germination, ginning out turn, staple length, and staple fineness contributed with 91, 96, 96, 79, 43 and 73%, respectively, to the total variability at different densities of D. koenigii. Our findings demonstrated that D. koenigii has become potential major pest and causes quantitative and qualitative losses to transgenic cotton, hence, there is a need to develop appropriate control measures for controlling its population to avoid further losses.

Hierarchical Analysis of Variation in the Mitochondrial 16SrRNA Gene among Five Different Insect Orders

Nucleotide sequences from a 500 bp region of the 16SrRNA gene were analyzed for ten insect pests of five different orders to examine the patterns of variation within the gene fragment and the taxonomic levels for which it showed maximum utility in phylogeny estimation. A hierarchical approach was adopted in the study through comparison of levels of sequence variation among taxa at different taxonomic levels. Among them, partial 16SrRNA gene was amplified in ten insects of five different orders. As previously reported for many holometabolous insects, the 16SrRNA gene data is reported here for 5 different orders were highly AT-rich and exhibited strong site-to-site variation in substitution rate. The partial 16SrRNA genes of five out of ten insects were reported first time. Primers were made from blasting 2 different genera of the order Diptera. These primers were proven to be universal as it amplified the partial 16SrRNA gene in ten different insects across five different orders, Diptera, Coleoptera, Heteroptera, Lepidoptera and Hymenoptera. Later, a phylogenetic tree was also constructed for understanding and analyzing the relation of above five orders. This study resulted in unusual findings which were as follows: All the species of Drosophila of order Diptera were evolutionary more closely related to Dysdercus koenigii of order Heteroptera than Bactrocera cucurbitae of Drosophilan order, Diptera in terms of partial 16SrRNA gene sequence. Similarly, Spodoptera litura and Helicoverpa armigera belonged to same family Noctuidae whereas Pieris brassicae belonged to family Pieridae. All belonged to order Lepidoptera. The results showed that Spodoptera litura in terms of partial 16SrRNA gene sequence was evolutionary more close to Pieris brassicae than Helicoverpa armigera.

Suppression of dominant insect pests and yield of sesame with plant materials in different climatic conditions

Sesame (Sesamum indicum L.) is an annual herb not extensively cultivated in Bangladesh. The jute hairy caterpillar, Spilarctia (=Spilosoma) obliqua (Walker) was found to attack the foliages including tender shoots of sesame in the Oilseeds Cultivation Centre of BCSIR Laboratory Campus, Rajshahi. The other pests encountered were pentatomid bugs, Dolycoris indicus (Stal) and Nezara viridula (L.),a chrysomelid beetle, Aphthona nigrilabris (Duvivier), leaf sucking coleopteran beetle and Monolepta signata (Oliv.) The insect pests encountered in the Oilseeds Cultivation Centre, Patgram, Lalmonirhat were: a pyrrhocorid bug, Dysdercus koenigii Fab. and a pentatomid bug, Piezodorus hyubneri Gmelin (Fab.). The efficacy of five plant extracts or botanicals e.g., Bara Bishkatali (Polygonum orientale L.) leaf, custard apple (Annona squamosa L.) leaf, castor (Ricinus communis L.) seed oil and sesame oil (Sesamum indicum), a mixture of Neem (Azadirachta indica L.) seed oil and sesame oil have been evaluated for their pesticide action in the suppression of dominant insect pests of sesame. The treatment of custard apple leaf extract produced significant result in pest control and crop yield next to sesame oil. Other treatments also exhibited better results in comparison to the control. The yields were 858 and 642 kg per acre in the crop fields of Lalmonirhat and Rajshahi districts respectively. DOI: http://dx.doi.org/10.3329/bjsir.v49i1.18851 Bangladesh J. Sci. Ind. Res. 49(1), 31-34, 2014

Effect of Host Plant on Survivability, Development and Reproductive Potential of Cotton Stainer BugDysdercus koenigii(Hemiptera: Pyrrhocoridae)

Red cotton bug Dysdercus koenigii F. (Hemiptera: Pyrrhocoridae) is a serious destructive pest of a large number of economically important crops including cotton. Being pest of many important crops, the present study was intended to investigate the comparative survivability, developmental rates, weight gain and reproductive potential of D. koenigii on five different host plant species, namely, okra (Abelmoschus esculentus), ground nut (Arachis hypogaea) yellow corn, (Zea mays) castor (Ricinus communis) and cotton (Gossypium hirsutum) under laboratory conditions. Maximum nymphal survivability, high nymphal weight, maximum egg production and egg hatching as well as shortest nymphal duration were observed on cotton as compared to okra, ground nut and yellow corn; however, castor was recorded as very poor host plant that could not support the survival and development of D. koenigii beyond 3rd instar. The adults emerged from the cotton and okra fed nymphs mates 3–4 times in their total life span, whereas only 1–2 time mating was observed in those adults that emerged from ground nut and yellow cord-fed nymphs. On the basis of nymphal and adult survivability, weight gain, egg production, egg hatching and longevity, the cotton (G. hirsutum) was regarded as a best host plant followed by okra (A. esculentus), ground nut (A. hypogaea) and yellow corn (Z. mays). The knowledge obtained during this study regarding food preference of D. koenigii may help in devising IPM strategies in cotton fields adjacent to or near vegetative fields containing alternative host plant.

Hybrid molecules of carvacrol and benzoyl urea/thiourea with potential applications in agriculture and medicine

Benzoyl phenyl urea, a class of insect growth regulator’s acts by inhibiting chitin synthesis. Carvacrol, a naturally occurring monoterpenoid is an effective antifungal agent. We have structurally modified carvacrol (2-methyl-5-[1-methylethyl] phenol) by introducing benzoylphenyl urea linkage. Two series of benzoylcarvacryl thiourea (BCTU, 4a–f) and benzoylcarvacryl urea (BCU, 5a–f) derivatives were prepared and characterized by elemental analysis, IR, 1H and 13C NMR and Mass spectroscopy. Derivatives 4b, 4d, 4e, 4f and 5d, 5f showed comparable insecticidal activity with the standard BPU lufenuron against Dysdercus koenigii. BCTU derivatives 4c, 4e and BCU 5c showed good antifungal activity against phytopathogenic fungi viz. Magnaporthe grisae, Fusarium oxysporum, Dreschlera oryzae; food spoilage yeasts viz. Debaromyces hansenii, Pichia membranifaciens; and human pathogens viz. Candida albicans and Cryptococcus neoformans. Compounds 5d, 5e and 5f showed potent activity against human pathogens. Moderate and selective activity was observed for other compounds. All the synthesized compounds were non-haemolytic. These compounds have potential application in agriculture and medicine.

Impact of Bt transgenic cottons and insecticides on target and non-target insect pests, natural enemies and seedcotton yield in India

Genetically engineered cottons expressing ä-endotoxins from Bacillus thuringiensis have been adopted on a large- scale worldwide. Therefore, we studied the efficacy of Bt cottons for the management of bollworms, their effects on non- target insects, and seedcotton yield under insecticide protected and unprotected conditions. Helicoverpa armigera and Earias vittella damage was significantly lower in Bt than in non-Bt cottons, while no significant differences were observed in egg-laying by H. armigera. The populations of major non-target sucking insect pests such as Amrasca biguttula biguttula, Bemisia tabaci, Aphis gossypii, Oxycarenus laetus, Dysdercus koenigii and Nezara viridula and the generalist predators, viz Cheilomenes sexmaculatus, Chrysopa spp., and spiders did not differ significantly between Bt and non-Bt cottons. Insecticide application resulted in resurgence of cotton aphid and whitefly, possibly because of elimination of natural enemies or better growth of plants uder protected conditions. Abundance of bollworms, non-target pests, and generalist predators was significantly greater before insecticide sprays than after insecticide application, except in a few cases. Bollworm damage was lower and seedcotton yields higher in Bt than in non-Bt cottons. The present studies indicated that Bt cotton hybrids are effective for the management of bollworms and yield more, and do not have any adverse effects on the abundance of generalist predators.

Design and development of novel insect growth regulators: Synthesis, characterization and effect of benzoyl thymyl thioureas and ureas on total haemocyte count of Dysdercus koenigii

Insect-growth regulators (IGRs) have been receiving foremost attention as potential means of selective insect control. Benzoyl phenyl urea (BPU) is a well-known IGR having chitin synthesis inhibitor activity. Mimics of BPU have been synthesized by suitable derivatization of a naturally occurring monoterpenoid, thymol (2-isopropyl-5-methyl phenol) to form a = series of substituted benzoyl thymyl thioureas (BTTUs) [IVa-f] and benzoyl thymyl ureas (BTUs) [Va-f]. The synthesized compounds have been characterized by 1H and 13C NMR, LC-MS and elemental analysis. These derivatives have been screened for their effect on total haemocyte count of Dysdercus koenigii. It has been observed that the introduction of substituted benzoyl thiourea and urea linkage into a thymol ring via an amino group results in higher activity than the parent compound thymol and a comparable pattern of results with the standard insect-growth regulators, Penfluron. Urea [Va-f] compounds exhibited greater effect on Total Haemocyte Count (THC) than thiourea [IVa-f]. Fluoro substitution enhanced the effect on THC more than chloro substituted compounds, while ortho-substitution resulted in a better effect than para-substitution. The results described in this paper are promising and provide new array of synthetic chemicals that may be utilized as insect growth regulators.

Toxicity assessment of chlorpyrifos, λ-cyhalothrin and neem extract against Dysdercus koenigii with reference to survivorship, fecundity and some biochemical parameters.

–The present study was designed to evaluate the comparative toxicity of Chlorpyrifos, Lambda (λ) Cyhalothrin and Neem extract (a bio pesticide) against the adults of D. koenigii. A gradual increase in the mortality was found with the increase of concentration. The calculated LC50 values for Chlorpyrifos, λCyhalothrin and Neem extract were 0.0069%, 0.045% and 0.0787% respectively. The order of efficacy of the three pesticides in respect of toxicity was: Chlorpyrifos > λ. Cyhalothrin > Neem extract. Effect on fecundity of adult D. koenigii was investigated and it is observed that complete egg inhibition occurred at concentrations of 0.0062%, 0.0039% and 0.048% for Chlorpyrifo, λ. Cyhalothrin and Neem extract respectively. This showed that the three pesticides are same in the order of efficacy regarding toxicity and fecundity. Neem extract was found more effective to decrease the total protein content as compared with Chlorpyrifos and λ-Cyhalothrin. Inhibitory effects on GOT (Glutamate Oxaloacetate Transaminase) enzyme were calculated based on Spectrophotometeric analysis and found to be 10.2% (λ-Cyhalothrin) and 4.9% (Neem extract) where as Chlorpyrifos caused an increase in GOT activity up to 1.28% against the survivorship. The overall efficacy of the three pesticides against the survivorship was in the order of Chlorpyrifos > λ Cyhalothrin > Neem extract. This report covers effectiveness of the given pesticides in respect of various biochemical parameters GOT, Protein content, toxicity, fecundity and survivorship against the adults of D.Koenigii. Keywords––Dysdercus koenigii, Toxicity, GOT, Fecundity.

Relationship Between Weather Factors and Sucking Pests of Okra in Mizoram

The population dynamics of Aphis gossypii (Glover), Dysdercus koenigii Fabr. and Amrasca biguttula biguttula (Ishida) with respect to meteorological parameters on okra was conducted at the experimental farm, ICAR Research Complex for NEH Region, Mizoram Centre, Kolasib, Mizoram. The results revealed that a decrease in minimum temperature and minimum relative humidity and maximum relative humidity and increase in maximum temperature by 30 to 40% favour the population buildup of A. gossypii. Whereas an increase in temperature coupled with dry weather and decreased relative humidity favoured the build-up of A. biguttula biguttula. Peak population of D. koenigii was recorded as soon as maximum and minimum temperature was below 24 and 320C, respectively and minimum relative humidity and maximum relative humidity crossed 58 and 81%, respectively.

A new species of Hemipteroseius (Acari: Otopheidomenidae) parasitic on Dysdercus (Hemiptera: Pyrrhocoridae) in India

A new species of ectoparasitic mite, Hemipteroseius vikrami n. sp. (Mesostigmata: Otopheidomenidae), collected on Dysdercus koenigii (Fabricius) in New Delhi and D. cingulatus (Fabricius) in Varanasi, India is described. It is distinguished from other species of the genus in having the dorsal shield divided, podonotal shield with nine pairs and opisthonotal shield with four pairs of setae; setae j6, s6 and Z5 with bulbose/spatulate tips; tritosternum with two short slightly barbed lacinae; venter with four pairs of sternal setae, one pair on the sternal shield and three pairs placed posterolaterally; anus terminal; one pair of preanal setae; movable digit of chelicera with two teeth distally; macrosetae on genu I–IV and femur I–II with bulbose/spatulate tip. A list of species of Otopheidomenidae with details of distribution and hosts, key to species of Hemipteroseius and comparison of morphological characters of species are also provided.