Larval morphology and life history of Ascalaphus dicax Walker, 1853 (Neuroptera: Myrmeleontidae, Ascalaphinae)

Hyphantria cunea is one of the most important pest insects causing significant damage in many plant species. The present study aimed to evaluate the insecticidal activity of Turkey isolates of Beauveria bassiana and Metarhizium anisopliae against H. cunea larvae under laboratory and field conditions. B. bassiana isolates YK16, YK23 and YK26, and M. anisopliae isolates YK41 and YK45 were sprayed onto the larvae of H. cunea at the respective doses of 1x105 and 1x106 conidia mL-1 and monitored for seven days. Fungal isolates, bio-insecticide Bacillus thuringiensis and chemical insecticide diflubenzuron were used in field studies. Trials were carried out in five replications. All B. bassiana isolates caused 100% mortality on first instar larvae in laboratory trials. Mortality ratios ranged from 100 to 96% on second instar larvae. M. anisopliae isolates YK45 and YK41 caused 88 and 84%, and 81.33 and 77.11% mortalities for the first and second instar larvae, respectively. The mortality rates fluctuated between 91.78-72.89% for B. bassiana on third instar larvae in laboratory conditions. However, M. anisopliae isolates YK45 and YK41 caused 77.11 and 60.22% mortality on third instar larvae, respectively. In the field trials, B. bassiana YK23 displayed promising insecticidal activity with 80.60% mortality on second instar larvae of H. cunea. Other isolates as well caused mortalities ranging from 60.77 to 49.55%. The results revealed that some isolates of B. bassiana and M. anisopliae have potential to control H. cunea larvae. However, additional detailed studies need to be carried out to increase their effectiveness in field conditions.

Individual unique colour patterns of the pronotum of Rhynchophorus ferrugineus (Coleoptera: Curculionidae) allow for photographic identification methods (PIM)

Coleoid cephalopods camouflage on timescales of seconds to match their visual surroundings. To date, studies of cephalopod camouflage-to-substrate have been focused primarily on benthic cuttlefish and octopus, because they are readily found sitting on the substrate. In contrast to benthic cephalopods, oval squid (Sepioteuthis lessoniana species complex) are semi-pelagic animals that spend most of their time in the water column. In this study, we demonstrate that in captivity, S. lessoniana Sp.2 (Shiro-ika, white-squid) from the Okinawa archipelago, Japan, adapts the coloration of their skin using their chromatophores according to the background substrate. We show that if the animal moves between substrates of different reflectivity, the body patterning is changed to match. Chromatophore matching to substrate has not been reported in any loliginid cephalopod under laboratory conditions. Adaptation of the chromatophore system to the bottom substrate in the laboratory is a novel experimental finding that establishes oval squid as laboratory model animals for further research on camouflage.

Backgound: The black ladybird beetle, Stethorus sp. is a generalist predator whose larvae and adult prey on all developmental stages of the two-spotted red spider mite, Tetranychus urticae Koch. In order to develop a bological control program of T. urticae in the Mekong Delta of Vietnam , the predaotry efficacy of Stethorus sp. on T. urticae had been investigated. Methods: The investigation was conducted under the laboratory and net-house conditions at the College of Agriculture, Can Tho University. Result: Under laboratory conditions, fourth instar larvae exhibited the highest predation rate, while second instar larvae showed the lowest. Second instar larvae consumed an average of 65.63 eggs, 26.13 larvae, or 22.38 adults per day. In contrast, fourth instar larvae consumed 183.63 eggs, 88.63 larvae, or 73.63 adults per day. Adult female beetles consumed 149.38 eggs, 75.63 larvae, or 46.5 adults per day, while adult males showed lower consumption rates of 88 eggs, 62.25 larvae, or 36.13 adults per day. Under net house conditions, one pair of black ladybird beetles provided optimal control of the two-spotted red spider mites at a density of 56 mites per plant, with a control efficacy of 97.07 percent at 5 days post-release. At a red spider mite density of 168 individuals per plant, 4 and 6 pairs of black ladybird beetles demonstrated superior control efficacy of 93.02 percent and 99.54 percent respectively at 5 days post-release.

Biopesticides are the most reliable strategies to protect crops at the initial stages of pest attack. The present investigation was conducted to identify effective entomopathogenic actinomycetes for management of Fall Armyworm (FAW). Of 24 actinomycetes that were previously screened against 2nd instar larvae of FAW, three isolates were identified as effective, viz., KG-13, CAI-134 (Nocardiopsis sp.), and CAI-17 (Streptomyces albus) which showed mortality more than 50 %. These three promising isolates were selected for further evaluation using their Intracellular Metabolites (ICM) and Extracellular Metabolites (ECM) in both laboratory and greenhouse conditions. Under laboratory through diet impregnation bioassay, KG-13 caused maximum mortality in 2nd instar larvae of FAW, with both ECM (85.19%) and ICM (70.37%). Larval prolongation (22.57 ± 1.98 days) and larval pupal intermediates were observed in the ECM of CAI-17. In the evaluation of chitinase activity, the highest zone of inhibition was recorded in KG-13 (34.67 mm), followed by CAI-17 (25.33 mm) and CAI- 134 (19.67 mm). ECM of KG-13, CAI-17 and ICM of KG-13 were noticed with 66.66, 53.33 and 53.3 % mortality in greenhouse studies. This study shows the impact of promising actinomycetes secondary metabolites on the 2nd instar FAW and their effectiveness in both laboratory and greenhouse conditions. Comparatively, less mortality was noticed in the greenhouse than in laboratory conditions, whereas Bt var. kurstaki (73.33%) and Emamectin (73.33%) in greenhouse studies showed considerablemortality than actinomycetes metabolites.

Traditional pesticide formulations have some shortcomings, including limited efficacy and the usage of huge amounts of insecticide, which has a negative impact on the environment. Using nano‐pesticide formulations reduces the amount of pesticide applied, minimizing pest control expenses and environmental contamination. As a result, this study was conducted to develop a microemulsion formulation containing emamectin benzoate or beta‐cyfluthrin with improved morphology, droplet size, emulsion stability, and persistence of foam. Moreover to assess the efficacy of the developed microemulsion in comparison to the convention alone against the Egyptian cotton leaf worm, Spodoptera littoralis (Boisd.) under both laboratory and field conditions. The results showed that the optimum conditions for emamectin benzoate microemulsion was 2% active ingredient, 5% (w/w) ethyl acetate, and DMF (3:2), 3.5% (w/w) Geronol ff4 and Etocas 35 (6:1), 5% (w/w) ethanol, and 86.5% (w/w) water, while for beta‐cyfluthrin, a 5.0% active ingredient, 15% (w/w) Solvesso 100 and ethyl acetate (2:1), 7.0% (w/w) Geronol ff4 and Etocas 35 (6:1), 10% (w/w) ethanol, and 68% (w/w) water. Under laboratory conditions, emamectin benzoate was more toxic than beta‐cyfluthrin to Spodoptera littoralis second and fourth instar larvae. Emamectin benzoate was more effective that beta‐cyfluthrin against Spodoptera littoralis in the field, whether as a microemulsion or a commercial product. Thus, microemulsions of tested insecticides with better formulation qualities may be more effective than traditional ones in controlling cotton leaf worm.

BackgroundEntomopathogens such as nematodes, bacteria and fungi are well recognized for their biocontrol potential. This study was carried out to examine the insecticidal properties of the Heterorhabditis bacteriophora Poinar, Beauveria bassiana Balsamo-Crivelli, Bacillus thuringiensis Berliner, individually and in combination against 3rd instar larvae of Spodoptera litura Fabricius (Noctuidae: Lepidoptera) under controlled laboratory and greenhouse conditions at Eternal University, Baru Sahib, Sirmaur, Himachal Pradesh.ResultsThe results demonstrated that the combined applications of the tested entomopathogens resulted in 100% insect mortality under the laboratory conditions. Among the individual concentrations, applications of 200 IJs/ml were noticed highly virulent with (98%) mortality, followed by B. thuringiensis (96%) and then by B. bassiana (92%). However, single treatments were also evaluated that further showed a highest mortality in the target pest by H. bacteriophora, followed by B. thuringiensis. Among the combined treatments by H. bacteriophora plus B. thuringiensis (200 IJs + 1 × 1012 CFU/cm2) more effective caused (100%) mortality were noticed in the laboratory and (28%) under the greenhouse conditions than H. bacteriophora plus B. bassiana (200 IJs + 1 × 1010 conidia/cm2) that caused (100%) mortality and (34%) damage under both, laboratory and greenhouse conditions.ConclusionLaboratory bioassay and greenhouse evaluation tests demonstrated that the combined sprayed treatments showed reliable and fast synergism. This study could be recommended to the farmers to control the pest.

Sudden loading of the spine is not only considered a risk factor for the development of low-back pain but also enables an evaluation of the stability of the spine when conducted under laboratory conditions. In the present study the upper spine was pulled in the anterior direction and the stiffness as well as activity in the erector spinae muscle was measured with different pre-tension in the erector spinae. The results showed that increased activity in the erector spinae prior to loading led to increased stiffness (stiffness coefficients from 297 Nm rad(-1) to 438 Nm rad(-1)) and a decrease in the extra neural signal input to the muscles to maintain the stability. It is therefore clear that increased tension in the erector spinae muscle will create a larger stability of the spine to anterior perturbations. However, contracting the muscles around the spine increases the load on the spinal structures. In 34% of the experiments a silent period in the electromyographic signal was present after loading in the period when the torso was moving in the anterior direction. This phenomenon is discussed.

Maize stem borer (Chilo partellus swinhoe) is one of the major threatening global pests of maize and considered as the national top priority entomological research problem in Nepal. The Life cycle of maize stem borer was studied under laboratory condition at National Maize Research Program (NMRP), Rampur, Chitwan, Nepal during 2018. Development of stem borer undergoes following stages like egg, larvae, pupa and adult. Eggs and different instars of maize stem borer larvae were collected from maize fields were put with host materials (maize leaf and stem) to become different instars of larva, pupae and finally turned to adults. Eggs were harvested from adults and kept on blotting paper which was kept inside petriplates and reared for adults. Their life span in each stage (egg, larva and pupa) and the fecundity of adults recorded. Daily room temperature and relative humidity (RH) in laboratory conditions were recorded. The Egg incubation period ranged from 4-7 days and hatched generally in the early morning (6-8 AM). The complete larvae period ranged from 29 to 36 days while pupal period was ranged from 7 to 12 days. The average male pupal length was found 13 mm and female was 16 mm long. The fecundity of C. partellus Swinhoe was recorded 150-160 eggs per female. The Oviposition period was 4 days and adult male survived for 4-7 days while female for 4-9 days. The average life cycle of C. partellus completed in (44-48) days during summer whereas (60-64) days during winter at average room temperature of (26-27° C) and RH of (70-80%). These results have important implications to know the survival and development of pest including effective pest management strategy.

Seven spot ladybird beetle, (Coccinella septempunctata) is a widely distributed natural enemy of soft-bodied insect pests especially aphids worldwide. Both the adult and larvae of this coccinellid beetle are voracious feeders and serve as a commercially available biological control agent around the globe. Different techniques are adopted to enhance the mass rearing and storage of this natural enemy by taking advantage of its natural ability to withstand under extremely low temperatures and entering diapause under unfavorable low temperature conditions. The key objective of this study was to develop a cost effective technique for enhancing the storage life and predatory potential of the larvae of C. septempunctata through cold storage in conjunction with the use of nuclear techniques, gamma radiations. Results showed that the host eating potential of larvae was enhanced as the cold storage duration was increased. Gamma irradiation further enhanced the feeding potential of larvae that were kept under cold storage. Different irradiation doses also affected the development time of C. septempuntata larvae significantly. Without cold storage, the lower radiation doses (10 and 25 GY) prolonged the developmental time as compared to un-irradiated larvae. Furthermore, the higher dose of radiation (50GY) increased the developmental time after removal from cold storage. This study first time paves the way to use radiation in conjunction with cold storage as an effective technique in implementation of different biological control approaches as a part of any IPM programs

BackgroundUnder laboratory and greenhouse conditions, the virulence of 2 isolates of Thai indigenous entomopathogenic nematodes (EPNs) in controlling the fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera; Noctuidae), was demonstrated. Six EPNs dosages were tested against 2 larval instars of FAW under the laboratory conditions, while 2 different concentrations were tested under the greenhouse conditions.ResultsThe results of a laboratory experiment revealed that 2 Thai indigenous EPNs isolates (Heterorhabditis indica isolate AUT 13.2 and Steinernema siamkayai isolate APL 12.3) were efficient against the FAW, 2nd and 5th larval instars. Six different nematode concentrations (50,100, 150, 200, 250 and 300 infectious juveniles (IJs) ml−1) were evaluated, and all were proven to be effective, with the mortality rate associated with concentration. Inoculated larvae in the 2nd instar was more vulnerable than that in the 5th instar. H. indica isolate AUT 13.2 was more destructive than S. siamkayai isolate APL 12.3. The greatest mortality rate of 2nd instar larvae was 83% when H. indica AUT 13.2 was applied at the concentration of 250 IJs ml−1, and 68% when the nematode S. siamkayai APL 12.3 was used at the concentration of 300 IJs ml−1. At 250 IJsml−1, the highest mortality rate of the 5th instar larvae was 45% for H. indica AUT 13.2 and 33% for S. siamkayai APL 12.3, respectively. To customize the concentration and volume of nematodes suspension evaluated in the greenhouse settings, the most sensitive stage of FAW and the optimum concentration that caused the highest mortality were used. The concentrations of both indigenous nematodes’ isolates were 20,000 and 50,000 IJsml−1 per pot, respectively, and the results showed that the mortality rates were lower than that in the laboratory. FAW mortality rate was the highest (58%) in case of the nematode H. indica isolate AUT 13.2, against (45%) in case of S. siamkayai isolate APL 12.3, at the 50,000 IJs ml−1 concentrations.ConclusionsThe study revealed the 2 Thai indigenous EPNs isolates (H. indica isolate AUT 13.2 and S. siamkayai isolate APL 12.3) were capable of controlling the FAW in both laboratory and greenhouse environments. The 2 Thai EPNs showed the potential to be considered as a biological control agent.

The chilli thrips, Scirtothrips dorsalis Hood, mostly a leaf-thrips, has recently become a serious pest on rose flowers in India. For the first time its biology on rose flowers has been studied in the laboratory and field conditions at Bangalore, India. Under laboratory conditions, the egg, first, second instar larva, pre-pupal and pupal periods ranged from 3 to 5, 1 to 2.25, 2.25 to 3.75, 0.75 to 1.50 and 3.25 to 4.75 days, respectively. Pupation occurred on the curled portion of the flower petals. The total developmental period from egg to adult emergence ranged from 10.25 to 17.25 days. On average female laid about 2.3 eggs per day and lived for 4.65 days. In the field, the female laid the eggs singly into the tender leaves and occasionally in the flower petals. Pupation occurred in the leaf-litter and surface soil beneath the rose plants.

Studies on the biology and control of the peach tree borer, Sanninoidea exitiosa (Say), have been hampered by the inaccessibility of the larvae in its natural habitat and its extended period of larval development. A method of laboratory rearing is reported in which immature apples are employed as food for the larvae. The chief source of natural mortality, dessication of newly hatched larvae, is overcome under conditions of high humidity and ready access to food. The rate of larval development and number of instars is similar under laboratory and field conditions. There are normally 7 larval instars, the range in measurements of head capsule in later instars overlapping in field-collected larvae. Diapause in the larvae appears to be obligatory. Laboratory-reared moths deposited an average of 367 eggs each as compared with 515 for moths reared from field-collected pupae. Details of the rearing method are given and comparisons made in rates of larval development under field and laboratory conditions. Biological features are cited which are of special interest and which can be more readily studied with laboratory cultures. These include circadian rhythm in moth emergence and hatching, mating habits involving sex attractant by the female, and obligatory diapause in the larval stage. The species is readily adaptable to mass-rearing techniques.

Clitostethus arcuatus (Rossi) (Coleoptera: Coccinellidae) is considered as one of the most important natural biological control agents of the ash whitefly, Siphoninus phillyreae (Haliday) (Hemiptera: Aleyrodidae) in Iran. In the current survey, the development, survival, longevity, fecundity, feeding behaviour, and population dynamics of the predator under laboratory and field conditions were studied. The longevity of female insects was significantly longer than that of males. Total feeding of 4th larval instars and females was significantly higher than males and other larval instars. The overall mortality rate from egg to adult under laboratory conditions was 22.7% while under field conditions it was 38.2%. Copulation lasted approximately 67 minutes while the average pre-mating and pre-oviposition times recorded were 3.8 and 1.8 days, respectively. The mean number of eggs laid by each female was 181. The adults could survive starvation for 4 days with a normal longevity of 62–73 days. The maximum population density of the predator was recorded in late August that coincided with the decline of the S. phillyreae population. C. arcuatus had four generations per year, and the adults were observed until mid December. Possible application of C. arcuatus for biological control of S. phillyreae in integrated pest management programs is discussed.

A study on the Biology of the palm weevil Rhabdoscelus maculatus was carried out at Tropiflora Ornamental Palm Nurseries in Sri Lanka. This weevil, an important pest of ornamental palms, was detected for the first time in Sri Lanka at Tropiflora Nurseries. Although the incidence of this weevil is restricted to ornamental palms at present, there is a potential threat of the weevil becoming a pest of important cultivations such as coconut and sugarcane. The present investigation was therefore, carried out to con-firm the identification of this weevil and to study its biology. The identification of the palm weevil was confirmed as R. maculatus Gyllenhal, 1838 and is the first record in Sri Lanka. Biological, morphological and behavioural aspects of the weevil were studied under laboratory, semi-natural and natural conditions. The adult is a small, reddish-brown weevil (10.38-12.62 mm in length) with two black markings on the elytra and two on the thorax. The female is slightly larger than the male. The rostrum of the female is longer and more curved than that of the male. The ventral surface of the rostrum is roughened in the male while it is smooth in the female. Adult weevils are nocturnal in habit and hide in plant sheaths and debris during the day. They fly only short distances at a time but flight during the day was not observed. Mature female lays eggs inside cavities made in the leaf sheath. Under laboratory conditions, the period for egg incubation is 5.00 + 0.82 d. The larva is creamy white and legless with a round, highly sclerotized, reddish brown head capsule. Larvae feed on stem tissues rapidly and make tunnels. The frequency distribution analysis of head capsule width revealed six larval instars. Early weevil infestation of palms is indicated by a jelly like substance oozing out of the holes in the leaf sheaths. R. maculatus larva takes about 7.75+ 3.70 weeks to complete its development and then pupate inside a cocoon made of tightly bound, fibrous material completing the pupal stage in 2.50 + 0.76 weeks. The total life cycle of this weevil is completed in 10-12 weeks. The life span of adult weevils is between 8-10 months under semi-natural conditions and four weevil generations per year occur under natural conditions. DOI: http://dx.doi.org/10.4038/tare.v14i3.4845 Tropical Agricultural Research & Extension 14(3): 2011 70-75