Fazil Hasan

Effect of different cole crops on the biological parameters of Pieris brassicae (L.) (Lepidoptera: Pieridae) under laboratory conditions

The effect of different cole crops was studied on biological parameters of Pieris brassicae (L.) in the laboratory at 28 °C, 65% RH, and 12L:12D photoperiod. The results indicated that host plants significantly affected the life history, i.e. survival of developmental stages, oviposition period, and sex ratio of P. brassicae. Comparative study on different host plant revealed that P. brassicae required a maximum of 40 days to complete generation on cabbage, cauliflower, and broccoli. The survivorship and expectation of life declined gradually with the advancement of age; the life expectancy of newly deposited eggs was 23.96 days while it was 8.12 days at the time of adult emergence on cabbage. However, the fluctuations of mortality parameter were seen on all the cole crops. On cabbage, 100% hatching of eggs with low larval mortality were noticed. The highest net reproductive rate (R0) occurred on cauliflower, i.e. 27.1 followed by cabbage 24.89, females per female per generation. Intrinsic rate of increase (rm), was found to be highest (0.09558954) on cauliflower followed by broccoli and cabbage, 0.078886 and 0.077551 females per female per day, respectively. The smallest rm (0.059469 females per female per day) occurred on radish which shows that P. brassicae did not perform well on radish. In addition, P. brassicae may double in 7.2 days on cauliflower, 8.7 days on broccoli, and 8.9 days on cabbage. The sex ratio was computed as 1.5:1, female:male, respectively on cabbage.

Superparasitism in Cotesia glomerata does not benefit the host plant by reduction of herbivory caused by Pieris brassicae

Superparasitism occurs in Cotesia glomerata L. (Hymenoptera: Braconidae), a gregarious endoparasitoid of Pieris spp. (Lepidoptera: Pieridae). The responses of Pieris brassicae L. larvae to superparasitism were examined in order to elucidate the ecological significance of this behaviour. Models of tritrophic interactions often imply that attraction of herbivore natural enemies by the plant constitutes a defence. Parasitoid attack on herbivores is assumed to result in a reduction in herbivory and or an increase in plant fitness. Coupled with the active involvement of the plant in producing signals, this can be seen as an indirect mediation of wound induced defence. The results show that superparasitism of P. brassicae by the parasitoid C. glomerata reduced survivorship but increased food consumption and weight growth in P. brassicae larvae. The duration of host larval development was found prolonged as the number of oviposition increased and superparasitized larvae (three to five time parasitized) grew slower than unparasitized larvae or larvae parasitized one or two times.

Potential of Biopesticides in Sustainable Agriculture

Sustainable agriculture also aims at increasing the yield of food and fiber crops and reducing the incidence of pests and diseases to such a degree that they do not cause extensive damage to crops. With the advent of chemical pesticides in 1940s, this crisis was resolved to a great extent. But the overdependence on chemical pesticides and eventual uninhibited use of them has caused serious health and environmental problems. This concern has encouraged researchers to look for better alternatives to synthetic pesticides. Biopesticides can make important contribution to sustainable agriculture and help reduce reliance on chemical pesticides. microbial insecticide likeBacillus thuringiensis (Bt) produces a proteinic toxin which induces paralysis of the midgut and brings about cessation in feeding after being ingested by insect pests. Other promising candidates areBeauveria bassiana andMetarrhizium anisopliae. The spores penetrate the host cuticle, once inside the body, producing toxic metabolites called beauvericin (B. bassiana) and destruxins(M. anisopliae) responsible for death of the insects. Baculoviruses (Nuclear Polyhedrosis Virus and Granulosis Virus) are safe to human beings and wildlife, their specificity is very narrow. They do not infect beneficial insects and have capacity to persist in the environment, making them very suitable for use in sustainable agriculture. Semiochemicals: attractants and pheromones, and botanicals are important sources of agrochemicals used for the management of insect pests. They degrade rapidly and therefore, are considered safer than chemical pesticides to the environment.

Threats to fruit and vegetable crops: Fruit flies (Tephritidae) - ecology, behaviour, and management

Approximately 4,000 known/described species of fruit flies (Tephritidae) are distributed in tropical, subtropical, and temperate regions of world, out of which 200 species are economically important and damaging/spoiling not only to fruits but also to a number of vegetable crops. Despite their tremendous importance, a limited amount of information is available on the ecology and behaviour of fruit flies especially when compared to fruit fly species complex. It is necessary to understand the ecology and behaviour before the formulation of management strategy. The present review may serves as a baseline data for scientists engaged in fruit fly management programs. Key themes include: (1) demography and population dynamics and, (2) behaviour (e.g. sexual, mating, oviposition, and feeding). The excess of literature on monitoring and management of fruit flies are available, which includes male sterilization and annihilation, mass trapping, chemical baits, mating disruption, and biological control. But few of them are easily adopted by users and give satisfactory control of fruit flies and rest are not easily adopted or if used does not give effective control, because of the lack of knowledge about the ecology and behaviour of fruit flies. If the information on population dynamics, behavior, and the related ecological factors are not jointly gathered, it is almost impossible to carry out an appropriate pest control at the right time and place. We hope that this synthesis will lay the groundwork for future ecological and behavioural studies of fruit fly species, populations, communities, and control.

Microbial Insecticides: Food Security and Human Health

Sustainable agricultural systems must be adopted to increase the food and fiber production keeping in view of human health and increase in population; the number of undernourished has increased to almost 20% (The state of food insecurity in the world economic crises – impacts and lessons learned. In Food and Agriculture Organization of the United Nations, Rome). Insect pests have been causing serious damage in the fields and stored grains and their products. Interventions is required to limit the losses, therefore, synthetic insecticides have played a significant role in their management for more than 60 years. Indiscriminate use of insecticides have left undesirable residues in the environment, which are toxic to human beings and non target organisms as well as insects have developed resistance against them and resurgence of pests that lead to find a suitable, sustainable and efficient method of management. Microorganisms: bacteria, viruses, fungi and protozoa form the most abundant and diverse groups, which offer a vast resource for exploitation to use in the management program. Bacillus thuringiensis is a gram positive, occurs in soil and ubiquitous in distribution. It produces parasporal crystalline body which contains one or more cry proteins that can be toxic to a number of insects. cry proteins are encoded by cry genes and 200 of them are identified. Similarly, a number of insect pests are also vulnerable to viral diseases. Nuclear Polyhedrosis and Granulosis Viruses are commonly used against the Lepidoptera. They are highly species specific and safer to human beings. Fungi, often act as important natural control agents that limit the insect population. Promising results are obtained by Beauveria bassiana and Metarhizium anisopliae against many insect pests. B. bassiana grows naturally in soil throughout the world and causes white muscardine disease. Therefore, intensive work is required to improve the efficacy of microbial insecticides through molecular biology and genetic engineering to enhance their role in the insect management for better food security.

RETRACTED ARTICLE: Foraging of Host-Habitat and Superparasitism in Cotesia glomerata : A Gregarious Parasitoid of Pieris brassicae

The study investigates differences in the oviposition pattern of a braconid parasitoid, Cotesia glomerata (Linn.) in Pieris brassicae (Linn.) in relation to their use of different cruciferous food plants. The response of P. brassicae to superparasitism and consequences for the parasitoid were examined in order to elucidate the ecological significance of this behaviour. Female parasitoid located various crucifers and searched for host more frequently almost on all the host plants tested i.e. cabbage, cauliflower, Chinese cabbage, broccoli and radish. According to the estimated relative number of female locating hosts, cabbage was the most attractive plant for C. glomerata and total number of eggs laid in host larvae feeding on it was higher than in larvae feeding on other plants. Laboratory experiments demonstrated that superparasitism reduced survivorship of P. brassicae larvae. Superparasitism lengthened parasitoid development and prolonged the feeding period of host larvae. Sex ratio and the body weight of emergent wasps correlated negatively with brood size. Despite a trade-off between maximising brood size and optimising the fitness of individual offspring, two or three ovipositions on P. brassicae larvae resulted in a greater female dry mass than did a single oviposition on the host. Thus, superparasitism might be of adaptive significance under certain circumstances, especially when host density is low and unparasitized hosts are rare in a habitat.

Non-target toxicity of synthetic insecticides on the biological performance and population growth of Bracon hebetor Say

Bracon hebetor Say (Hymenoptera: Braconidae) is an important biological control agent of various species of order Lepidoptera and extensively used in biological control program worldwide. Present study evaluated the lethal and sublethal effects of insecticides on B. hebetor using demographic and population growth parameters. Doses of all the tested insecticides were within a maximum range of their recommended field dosages and adults were treated using residual glass vials method. For control experiments adults were treated with distilled water. Among the tested insecticides, the survivorship of various stages of B. hebetor was considerably prolonged on cyantraniliprole followed by chlorantraniliprole and shortest on chlorpyrifos and profenofos treated group. Total immature development time was prolonged in chlorpyrifos and profenofos treated group. Population growth parameters like intrinsic rate of natural increase (rm), net reproductive rate (R0), finite rate of increase (λ) and mean generation time (Tc) were considerably reduced in B. hebetor groups treated with chlorpyrifos and profenofos. However, B. hebetor groups treated with chlorantraniliprole and cyantraniliprole showed a little or no much difference in population growth parameters when compared with untreated group. It was also observed that chlorpyrifos and profenofos modified the sex ratio, thereby female emergence get reduced. On the basis of present findings it can be concluded that all tested insecticides caused considerable ecotoxic effects on B. hebetor compared to control. However, comparisons among the tested insecticides on the basis of IOBC criteria showed that chlorantraniliprol and cyntraniliprol was less toxic as compared to other insecticides tested on this biological control agent.

Toxic effects of insecticides on the life table and development of Earias vittella (Lepidoptera: Noctuidae) on okra

Okra, Abelmoschus esculentus (L.) Moench, is an important vegetable crop grown throughout the tropical and temperate regions of the world. Spotted bollworm, Earias vittella (Fab.), is one of the most important insect pests of okra. The effects of insecticides (cypermethrin, imidacloprid, carbaryl and neem oil) were studied on the fitness of the F1 generation of E. vittella by a demographic method. Life table was constructed from the eggs obtained by the surviving individuals that had ingested insecticides. Survivorship and expectancy was highest with the commencement of age and gradually decreased with the progression of age in the treatment groups and control. However, it was reduced in the treatment groups in comparison to control groups. Highest numbers of unhatched eggs (17%) were recorded with imidacloprid and cypermethrin treatments, whereas all the eggs hatched in control groups. Larval mortality was high in the initial instars as compared to late instars. Potential fecundity was significantly reduced to 94 females/female/generation treated with cypermethrin as compared to 256 in the untreated females. Developmental time of pre-pupa and pupa was significantly decreased with cypermethrin treatment. The intrinsic rate of increase was reduced to 0.0201 females/female/day in cypermethrin groups as compared to 0.046 in the control groups. The generation time was 33.27 days in the control, which was reduced to 26.78 days with carbaryl treatment and was increased to 37.5 days with neem oil. Insecticides cause adverse effect on the surviving generation of E. vittella, and may be incorporated as a valuable component in the integrated management of E. vittella on okra.

Studies of the effects of imidacloprid and deltamethrin insecticides on the biology of Pieris brassicae (Linn.) on cabbage.

The present investigation was conducted during Rabi season of 2011 to see the effect of imidacloprid and deltamethrin insecticides on the biology of Pieris brassicae (Linn.) on cabbage at experimental field of the Department of Plant Protection, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh. The larvae of Pieris brassicae were collected from cabbage field in the month of January and February 2012. They were kept in jars measuring 25 x15 cm and provided fresh cabbage leaves as food for larvae. These jars were kept in B.O.D chamber at 24.5 oC and 70±10 per cent relative humidity. Fresh cabbage leaves were dipped in 0.05 per cent aqueous solution of, imidacloprid and deltamethrin and dried at room temperature by keping in the experimental jars. Fifteen third instar larvae in a batch of five were allowed to feed on them for 24 hours. Survivorship and expectancy of the life was greatest in the beginning of the age and decreased gradually with the advancement of the age in the all treatment including control. The expectancy was minimum (17.18) when P. brassicae was treated with imidacloprid while maximum in the untreated individuals (25.83). The mortality of P. brassicae was significantly high in the early instars as compared to late instars in both treated and untreated individuals. How to view point the article : Khan, Hadi Husain, Ansari, M. Shafiq, Hasan, Fazil, Ahmad, Salman and Danish, Mohd. (2016). Studies of the effects of imidacloprid and deltamethrin insecticides on the biology of Pieris brassicae (Linn.) on cabbage. Internat. J. Plant Protec., 9(1) : 313-321.