Threshold Temperatures and Thermal Requirements for the Development of Spodoptera litura (Lepidoptera: Noctuidae)

Developmental thresholds and thermal requirements for different stages of Spodoptera litura (F.) fed on groundnut leaves were determined under constant laboratory conditions and in the field. An average of 64 degree-days (DD) above a threshold of 8°C was required from oviposition to egg hatch; the larval period required 303 DD and pupal stage 155 DD above a 10°C threshold; females needed 29 DD above a 10.8°C threshold from emergence to oviposition. Fifth and sixth instars accounted for about 50%of the total larval requirement under laboratory and field conditions. The response of various stages of S. litura to temperatures under constant laboratory conditions was similar to that under field conditions. The upper developmental threshold temperature of all stages was 37°C; 40°C was lethal

World review of the natural enemies and diseases of Spodoptera litura(F.)(Lepidoptera: Noctuidae)

Published information was used to compile a summary of natural enemies(parasitoids, predatorsand diseases) reported attacking Spodoptera litirra (F) under field conditions. Species (71) of insect parasitoids in seven families of Hymenoptera and two families of Diptera were listed as parasitoids of difTerent stages of S. litura. Predatory insects (36) belonging to 14 families and 12 species of spiders from six families have been reported to feed on this species. Four prolozoan, four fungal, seven bacterial, four each of viral and nematode species were also reported to be the pathogens of this species. Published information suggested that periodic releases of large number of egg parasites could help in suppressing populalions of this pest. There is a considerable scope for increased attention to the role of natural enemies as component of integrated pest management programmes of S. litura

Objective structured practical examination (OSPE) as a tool in formative assessment of II MBBS students, in pathology

Background: Assessment drives the student learning. Regular periodical assessment not only improves learning habits, but also enhances the competence in all levels of medical education. Traditional practical examination is more subjective. It depends on examiners subjectivity, varying difficulty level of various experiments, and also internal marks variation etc. These flaws can be overcome by newer methods like OSPE. The aim of the study was to implement OSPE as a tool of internal assessment for practical skills in the II MBBS. To compare this with traditional practical examination (TPE). To obtain the students and faculty feedback regarding OSPE as a tool of assessment.Methods: A cross sectional study was carried out for 158 students in II internal pathology practical examination for six days in the second week of September 2016 at Department of Pathology, Dr. Pinnamaneni Siddhartha institute of medical sciences & Research Foundation, Chinnaoutpalli. Faculty and students were sensitized; blueprint were used to arrange twenty OSPE stations for the exercises conducted as per TPE and for the same 25 marks as per TPE. Simultaneously, all the students were subjected to both TPE and OSPE at the same time and venue. TPE was assessed by two professors and OSPE by separate eight faculty members independently without interaction with the students. The procedural stations were evaluated by using checklist and the response stations which consisted of short answers and MCQs, facilitated correction. Feedback was given to the student on their performance and feedback was obtained from the students and faculty regarding OSPE by questionnaire with Yes/No answers.Results: Performance score of students in OPSE (13.73 ±2.49) was higher as compared to TPE (9.27±1.86) which was statistically significant. Based on the response to the questionnaire, students perception towards OSPE was analyzed. Majority strongly agree OSPE to be fairer, more transparent and objective in comparison to TPE. In contrast, all the faculty members unanimously opined that OSPE was difficult to arrange, time taken and faculty versus students ratio was high for evaluation. Though, the faculty (91%) overall opined that OSPE should be included as a method of assessment.Conclusions: Present study revealed that OSPE was acceptable, feasible and reliable to the students as well as for faculty for the internal assessment in pathology. Opinions of both students and faculties strongly agreed that OPSE is more effective objective assessment tool

Callosbruchus maculatus Resistance in Some Wild Relatives and Interspecific Derivatives of Pigeonpea

The present study of Screening of some wild relatives of pigeonpea against bruchid revealed that amongst the 4 Cajanus species, comprising of seven accessions, bruchid damage ranged between 14 and 30%, compared to 78% in the commercially cultivated pigeonpea variety ICPL 85010. Wild species Cajanus scarabaeoides accession ICPW 130 and C. platycarpus accession ICPW 66 had lowest damage (14% and 16% respectively). The larval/pupal period was prolonged in wild accessions (42 – 55days) compared to 33 days on the susceptible control ICPL 85010 indicating the antibiosis mechanism of resistance in the wild species. Though there was high oviposition on the seeds of interspecific derivative of C. platycarpus A 4-10-7-19, it had the least damage (10%). In the rest of the derivatives the damage rating ranged between 10 and 55% compared to 80% damage in the susceptible control, reflecting the potential of utilizing these wild species derivatives in pigeonpea crop improvement to overcome the Bruchid damage

Status of Insecticide Resistance in Spodoptera litura in Andhra Pradesh, India

Twenty-two strains of the tobacco caterpillar, Spodoptera litura (F.) (Lepidoptera: Noctuidae), collected from groundnut crops of eight locations in Andhra Pradesh, India, between 1991 and 1996 were assayed in the F1 generation for resistance to commonly used insecticides. Resistance levels ranged as follows: cypermethrin, 0·2- to 197-fold; fenvalerate, 8- to 121-fold; endosulfan, 1-to 13-fold; quinalphos, 1- to 29-fold; monocrotophos, 2- to 362-fold and methomyl, 0·7- to 19-fold. In nearly all strains pre-treatment with the metabolic inhibitor, piperonyl butoxide, resulted in complete suppression of cypermethrin resistance (2- to 121-fold synergism), indicating that enhanced detoxification by microsomal P450-dependent monooxygenases was probably the major mechanism of pyrethroid resistance. Pre-treatment with the synergist DEF, an inhibitor of esterases and the glutathione S-transferase system, resulted in a 2- to 3-fold synergism with monocrotophos indicating that esterases and possibly glutathione S-transferases were at least to some extent contributing to organophosphate resistance

Condensed tannin levels and resistance of groundnuts (Arachis hypogaea) against Aphis craccivora

A strong negative relationship was found between the concentrations of procyanidin, a condensed tannin, in the leaf bud petioles of seven genotypes of groundnut (Arachis hypogaea) and fecundity of the aphid Aphis craccivora on the same genotypes. Genotype EC 36892 contained the highest amount of procyanidin per weight of fresh petiole (ca 0.7%) and aphids feeding on this genotype produced significantly fewer offspring than aphids reared on genotypes with low procyanidin levels. It is proposed that testing for high procyanidin concentrations may provide plant breeders with a quick and relatively simple method to screen new groundnut genotypes for resistance against Aphis craccivor

Progress in Breeding Groundnut Varieties Resistant to Peanut Bud Necrosis Virus and its Vector

Peanut bud necrosis disease (PBND), caused by peanut bud necrosis virus (PBNV), and transmitted by Thrips palmi is an important disease of groundnut in South and Southeast Asia. Several cultivated groundnut germplasm lines showed consistently low disease incidence under field conditions (field resistance). Eight accessions of wild Arachis species did not show disease under field conditions. Field resistance could be due to vector and/or to virus resistance. The current breeding strategy includes improving the level of resistance to thrips and PBNV, and combining them into superior agronomic backgrounds. Several high-yielding varieties with high levels of resistance to PBND have been developed. These varieties possess moderate resistance to the vector. Two of these, ICGV 86031 and JCGV 86388, show resistance to PBNV when mechanically sap-inoculated with low virus concentration (10-2). Considering the level of resistance to the vector and PBNV, it appears that further improvement in the level of resistance through conventional breeding may be difficult to achiev

Seed Systems for Rainfed Agriculture: Village Based Seed Enterprise for Seed Production and Dissemination of Improved Varieties of Chickpea and Pigeonpea in India; Information Bulletin No. 96

The crops grown under rainfed agriculture are described as farming practices that rely on rainfall for crop production and their seed systems describe, how farmers in these regions are sourcing seeds for cultivating these crops. The objective of this publication is to share information and experiences of some success stories of seed value chain models developed for production and supply of improved varieties of seed of rainfed crops to resource poor farmers in the semi-arid tropical regions to enhance productivity. Majority of legume crop varieties grown under rainfed agriculture system are open pollinated varieties or self-pollinated crops especially, cereals and legumes grown in semi-arid tropics of the globe. The importance of rainfed agriculture varies regionally but produces high percentage of food for poor communities in the developing countries. In sub-Saharan Africa more than 95% of the farmed land is rainfed, while the corresponding figure for Latin America is almost 90%, for South Asia it is about 60%, 65% for East Asia and 75% for the Near East and North Africa..