Double zero tillage and foliar phosphorus fertilization coupled with microbial inoculants enhance maize productivity and quality in a maize-wheat rotation.

Maize is an important industrial crop where yield and quality enhancement both assume greater importance. Clean production technologies like conservation agriculture and integrated nutrient management hold the key to enhance productivity and quality besides improving soil health and environment. Hence, maize productivity and quality were assessed under a maize-wheat cropping system (MWCS) using four crop-establishment and tillage management practices [FBCT-FBCT (Flat bed-conventional tillage both in maize and wheat); RBCT-RBZT (Raised bed-CT in maize and raised bed-zero tillage in wheat); FBZT-FBZT (FBZT both in maize and wheat); PRBZT-PRBZT (Permanent raised bed-ZT both in maize and wheat], and five P-fertilization practices [P100 (100% soil applied-P); P50 + 2FSP (50% soil applied-P + 2 foliar-sprays of P through 2% DAP both in maize and wheat); P50 + PSB + AM-fungi; P50 + PSB + AMF + 2FSP; and P0 (100% NK with no-P)] in split-plot design replicated-thrice. Double zero-tilled PRBZT-PRBZT system significantly enhanced the maize grain, starch, protein and oil yield by 13.1-19% over conventional FBCT-FBCT. P50 + PSB + AMF + 2FSP, integrating soil applied-P, microbial-inoculants and foliar-P, had significantly higher grain, starch, protein and oil yield by 12.5-17.2% over P100 besides saving 34.7% fertilizer-P both in maize and on cropping-system basis. P50 + PSB + AMF + 2FSP again had significantly higher starch, lysine and tryptophan content by 4.6-10.4% over P100 due to sustained and synchronized P-bioavailability. Higher amylose content (24.1%) was observed in grains under P50 + PSB + AMF + 2FSP, a beneficial trait due to its lower glycemic-index highly required for diabetic patients, where current COVID-19 pandemic further necessitated the use of such dietary ingredients. Double zero-tilled PRBZT-PRBZT reported greater MUFA (oleic acid, 37.1%), MUFA: PUFA ratio and P/S index with 6.9% higher P/S index in corn-oil (an oil quality parameter highly required for heart-health) over RBCT-RBCT. MUFA, MUFA: PUFA ratio and P/S index were also higher under P50 + PSB + AMF + 2FSP; avowing the obvious role of foliar-P and microbial-inoculants in influencing maize fatty acid composition. Overall, double zero-tilled PRBZT-PRBZT with crop residue retention at 6 t/ha per year along with P50 + PSB + AMF + 2FSP while saving 34.7% fertilizer-P in MWCS, may prove beneficial in enhancing maize productivity and quality so as to reinforce the food and nutritional security besides boosting food, corn-oil and starch industry in south-Asia and collateral arid agro-ecologies across the globe.

Control of Aedes aegypti and Ae. albopictus, the vectors of dengue and chikungunya, by using pheromone C21 with an insect growth regulator: Results of multicentric trials from 2007-12 in India.

BACKGROUND & OBJECTIVES: Aedes mosquito control has gained much importance nowadays in view of rise in number of reported cases of dengue and chikungunya in India and other countries. In the present study, C21 attracticide (containing a pheromone and an insect growth regulator­IGR, developed by Defence Research and Development Establishment (DRDE), Gwalior, India was tested for its feasibility for surveillance and control of Aedes mosquito in a multicentric mode from October 2007 to June 2012 in urban (Delhi, and Bengaluru district, Karnataka) and suburban (Alappuzha district, Kerala) settings of the country in three phases. METHODS: Across the randomly selected households in each study area, two to four containers treated with attracticide (experimental) and untreated (control) were placed and monitored by trained surveillance workers on weekly/ fortnightly basis for determining the presence of eggs, larvae and pupae. Container positivity, percent larvae, egg and pupae collected were determined during different phases and analyzed statistically using SPSS 18.0. RESULTS: Container positivity was found statistically significant at Bengaluru and Alappuzha, Kerala while in Delhi, it was found non-significant. Eggs collected from experimental containers were significantly higher in comparison to control at all the locations except Delhi. Also larvae collected from control containers were significantly higher at all the locations except Bengaluru. Pupae collected from control containers remained significantly higher at all the locations as no pupal formation was recorded from experimental containers. INTERPRETATION & CONCLUSION: The use of C21 attracticide hampered pupal formation, thus inhibiting adult population in the study areas. The study established that C21 attracticide was efficacious in the field conditions and has potential for use in surveillance and management of dengue and chikungunya mosquitoes.

A note on the insecticide susceptibility status of principal malaria vector Anopheles culicifacies in four states of India.

BACKGROUND & OBJECTIVES: The major malaria vector, Anopheles culicifacies Giles is reported to contribute ~ 65% of the malaria cases in India. This species developed resistance to DDT and later to HCH, malathion and also to pyrethroids in some states due to their use in the national malaria control programme. In the present study, insecticide susceptibility of this species was monitored in four states of India. METHODS: To determine insecticide susceptibility status of the major malaria vector An. culicifacies, adult mosquitoes were collected from different localities of 32 tribal districts in the states of Andhra Pradesh, Odisha, Jharkhand and West Bengal during October/November 2009-10. Mosquitoes were collected from stratified ecotypes comprising a group of districts in West Bengal and individual districts in three other states. Mosquitoes were exposed to papers treated with WHO diagnostic dose: 4% DDT, 5% malathion and 0.05% deltamethrin following the WHO tube method. RESULTS: RESULTS provided the susceptibility status of An. culicifacies to different insecticides used in the public health programme in 32 districts in four states. An. culicifacies was found resistant to DDT (mortality range 0-36%) in all the 32 districts; to malathion it was resistant in 14 districts, verification required in 10 districts and susceptible in eight districts (mortality range 32.2-100%). It was resistant to deltamethrin in four districts, verification required in 11 districts and susceptible in 17 districts (mortality range 43.3-100%). INTERPRETATION & CONCLUSION: Development of widespread resistance to insecticides used in public health sprays for vector control including to pyrethroids in An. culicifacies in the surveyed districts is of great concern for the malaria control programme as the major interventions for vector control are heavily reliant on chemical insecticides, mainly synthetic pyrethroids used both for indoor residual spraying and for long-lasting insecticidal nets. Thus, there is a need to periodically monitor and update the susceptibility status of malaria vector(s) to suggest alternative vector control strategies for effective disease management.

Evaluation of indoor residual spray and insecticide treated bed nets in a malaria endemic area of Santhal Pargana, Dumka district (Jharkhand).

The study was carried out for evaluation of various activities of malaria control programme in five different tribal and malaria endemic Primary Health Centres of Dumka district (Jharkhand) during 2007-08. A total of 321 houses of 18 villages were surveyed on use of indoor residual spray (IRS) and insecticide-treated bed nets (ITN) and other activities as tool for vector control and interrupting the transmission of malaria. Out of 690 living rooms and 343 verandahs examined, IRS with Dichlorodiphenyl-trichloro-ethane (DDT) was done only in 16.23% living rooms and 64.72% verandahs. Refusal rate of IRS in living rooms was 81.93% due to lack of knowledge regarding the importance of IRS, no prior information to villagers, houses locked, reluctance to remove domestic articles, dislike of smell of DDT spray. Compliance rate of ITN uses was 71.66% during the night, which might be a factor for decline in malaria cases in the study area. Various important components of the programme, viz. surveillance and compliance to treatment activities, use of rapid diagnostic test kits (RDKs), involvement of accredited social health activist (ASHA's) and fever treatment depots (FTDs), laboratory activities, adult mosquito collection, other activities like constitution of village health sanitation committee, information education and communication activities, capacity building, use of larvivorous fishes, supervision of IRS etc. require much strengthening. However, 100% community acceptance was recorded for ITN in the villages surveyed. In addition, an entomological study was carried out for information on prevalence of mosquito species in this area to find out effectiveness of IRS activities. Eleven anopheline species, including three malaria vectors i.e., An. culicifacies, An. stephensi, An. fluviatilis, An. annularis, An. subpictus, An. nigerrimus, An. pallidus, An. aconitus, An. vagus, An. jamsii and An. splendidus were collected from cattle and human dwellings.

Toxicological properties of several medicinal plants from the Himalayas (India) against vectors of malaria, filariasis and dengue.

The leaves of five plants namely Nyctanthes arbortistis (Oleaceae), Catharanthus roseus (Apocynaceae), Boenininghusenia albiflora (Rutaceae), Valeriana hardwickii (Valerianaceae) and Eupatorium odoratum (Asteraceae) were selected for the first time from the Garhwal region of north west Himalaya to investigation its toxicological properties against mosquito vectors of malaria, filariasis and dengue. In a laboratory study, using different polarity solvents (petroleum ether, chloroform and methanol) were tested against important larvae of malaria, filariasis and dengue vectors in India. It was observed that petroleum ether fraction of all selected plant possess good larvicidal properties than other solvent fraction. The LC(50) values of isolates from Nyctanthes arbortistis (HAR-1), C. roseus (CAT-1), B. albiflora (BOA-1), V. hardwickii (SUG-1) and E. odoratum (EUP-1) against Anopheles stephensi were 185 ppm, 150 ppm, 105 ppm, 225 ppm and 135 ppm, respectively. The results therefore suggest that the fraction code BOA-1 has excellent larvicidal properties and could be incorporated as botanical insecticides against mosquito vectors with high safety to nontarget organisms. The same fraction was tested against adult vectors of malaria, filariasis and dengue, but no mortality was observed.

Laboratory colonization of Anopheles fluviatilis species T and U.

The populations of Anopheles fluviatilis James (1902), a foothill vector, collected from village Tilpuri of district Udham Singh Nagar and from villages Auspur, Ismailpur, and Durgapur of district Hardwar were maintained at National Institute of Malaria Research Insectory at 28 +/- 1 degrees C and 80-85% RH. Anopheles fluviatilis sensu lato was identified for two sibling species T and U. A total of 94% of the females of both species T and U oviposited by day 4 after the blood meal. Maximum hatching, that is, 80 and 62% of the eggs of species T and U, was observed on the second and third day, respectively. For species T, mortality in second and third instars was recorded to be 144 +/- 9 (N = 1,600) and 48 +/- 6 (N = 1,200), whereas in species U, it was 196 +/- 13 (N = 1,400) and 70 +/- 8 (N = 1,000), respectively. Mortalities in second instars of species T and U were significantly higher than third instars (P = 0.05). The female and male ratio in pupal stage of species T and U was found to be 53:47 and 58:42, respectively.

Prevalence of Aedes aegypti Linnaeus and Aedes albopictus Skuse in Koderma, Jharkhand.

Entomological survey was carried out in different localities of Koderma district of Jharkhand with a view to study the prevalence, distribution and stratification of areas for Aedes mosquito species. A total of 233 houses were covered during house to house larval and adult survey. Aedes breeding could be detected in 157 houses. In all, a total of 942 domestic water containers were searched, out of which 461 were found positive. The overall house index(HI) container index(CI) breteau index(B1) and pupal index(PI) were 67.38%, 48.94%, 197.85% and 79.4%, respectively. The survey revealed that Aedes aegypti Linnaeus and Aedes albopictus Skuse are well established in Koderma with most of the areas showing high adult and larval indices. The preventive strategy needs to be directed towards minimizing the breeding potential of Aedes and water management practice by individuals along with implementation of urban bye-laws as well as IEC activities to contain Aedes breeding in future.

Toxicological properties of several medicinal plants from the Himalayas (India) against vectors of malaria, filariasis and dengue

The leaves of five plants namely Nyctanthes arbortistis (Oleaceae), Catharanthus roseus (Apocynaceae), Boenininghusenia albiflora (Rutaceae), Valeriana hardwickii (Valerianaceae) and Eupatorium odoratum (Asteraceae) were selected for the first time from the Garhwal region of north west Himalaya to investigation its toxicological properties against mosquito vectors of malaria, filariasis and dengue. In a laboratory study, using different polarity solvents (petroleum ether, chloroform and methanol) were tested against important larvae of malaria, filariasis and dengue vectors in India. It was observed that petroleum ether fraction of all selected plant possess good larvicidal properties than other solvent fraction. The LC50 values of isolates from Nyctanthes arbortistis (HAR-1), C. roseus (CAT-1), B. albiflora (BOA-1), V. hardwickii (SUG-1) and E. odoratum (EUP-1) against Anopheles stephensi were 185 ppm, 150 ppm, 105 ppm, 225 ppm and 135 ppm, respectively. The results therefore suggest that the fraction code BOA-1 has excellent larvicidal properties and could be incorporated as botanical insecticides against mosquito vectors with high safety to nontarget organisms. The same fraction was tested against adult vectors of malaria, filariasis and dengue, but no mortality was observed.

Community awareness, perceptions, acceptability and preferences for using LLIN against malaria in villages of Uttar Pradesh, India.

BACKGROUND & OBJECTIVES: Long-lasting insecticidal nets (LLINs) have been introduced in India recently into the vector control programme. A study was undertaken to assess the community perception regarding use of LLIN, their acceptability, collateral benefits, etc. in certain villages of District Gautam Budh Nagar, Uttar Pradesh, India where LLINs are in use by the community. METHOD: A randomized community-based survey was undertaken during April- May 2009 covering 596 respondents in LLIN villages where LLINs have been distributed along with 307 respondents in untreated net villages where untreated nets were distributed using structured questionnaire. Qualitative data were collected and the difference in proportion was calculated by z-test. RESULTS: A substantial number of respondents had good knowledge of the symptoms of malaria. According to respondents, LLINs were very much effective in bringing down the malaria incidence in their families. About 98.3% of the respondents asserted the use of LLINs as their use not only reduced the number of mosquitoes as well as other non-target insects, but also reduced the malaria incidence. About 93.2% of the respondents were ready to purchase LLINs if available at nominal prices. All the respondents were satisfied about the performance of the LLINs in reducing the mosquito nuisance, safety of use and collateral benefits in LLIN villages. CONCLUSION: LLINs are safe, socially acceptable and should be promoted for vector control to reduce the disease burden in the communities.

Adulticidal activity of essential oil of Lantana camara leaves against mosquitoes.

BACKGROUND & OBJECTIVES: Development of insect resistance to synthetic pesticides, high operational cost and environmental pollution have created the need for developing alternative approaches to control vector-borne diseases. In the present study we have investigated the insecticidal activity of essential oil isolated from the leaves of Lantana camara against mosquito vectors. METHODS: Essential oil was isolated from the leaves of L. camara using hydro-distillation method. Bioassay test was carried out by WHO method for determination of adulticidal activity against mosquitoes. Different compounds were identified by gas chromatography-mass spectrometry analysis. RESULTS: LD(50) values of the oil were 0.06, 0.05, 0.05, 0.05 and 0.06 mg/cm(2) while LD(90) values were 0.10, 0.10, 0.09, 0.09 and 0.10 mg/cm(2) against Ae. aegypti, Cx. quinquefasciatus, An. culicifacies, An. fluvialitis and An. stephensi respectively. KDT(50) of the oil were 20, 18, 15, 12, and 14 min and KDT(90) values were 35, 28 25, 18, 23 min against Ae. aegypti, Cx. quinquefasciatus, An. culicifacies, An. fluviatilis and An. stephensi, respectively on 0.208 mg/cm(2) impregnated paper. Studies on persistence of essential oil of L. camara on impregnated paper revealed that it has more adulticidal activity for longer period at low storage temperature. Gas chromatographic-mass spectrometric analysis of essential oil showed 45 peaks. Caryophyllene (16.37%), eucalyptol (10.75%), alpha-humelene (8.22%) and germacrene (7.41%) were present in major amounts and contributed 42.75 per cent of the total constituents. INTERPRETATION & CONCLUSIONS: Essential oil from the leaves of L. camara possesses adulticidal activity against different mosquito species that could be utilized for development of oil-based insecticide as supplementary to synthetic insecticides.

Plasmodium falciparum gametocytaemia with chloroquine chemotherapy in persistent malaria in an endemic area of India.

BACKGROUND & OBJECTIVE: Gametocyte sex-ratio in Plasmodium falciparum malaria is an important determinant of transmission success and basis of disease epidemiology. Information on ratio of male to female gametocytes after an exposure of antimalarial regimens under field conditions is very limited. In this retrospective study we observed high densities of gametocytes along with high sex-ratio in P. falciparum cases, which may be responsible for persistent malaria transmission in this area. METHODS: Laksar PHC of Hardwar district, Uttarakhand State, India was selected because it contributed 90 per cent of the total malaria cases. A total of 568 uncomplicated P. falciparum malaria patients were assessed to investigate prevalence of gametocytes while 339 P. falciparum thick smears containing 5620 gametocytes were screened for measuring the gametocyte density for microgametocyte (male) and macrogametocyte (female). Homology of variance ('F' test) was checked on days 7 and 14 including the variables and risk factors namely fever, parasitaemia, gametocyte carriage in sensitive and resistant chloroquine treated P. falciparum cases. RESULTS: Slide positivity rate (SPR) increased drastically from 0.23 to 11.4 per cent with the predominance in P. falciparum infection after 1998. All 568 cases showed gametocytes in their peripheral blood, of which 109 (19%) were infected with rings and gametocytes and 459 (81%) had gametocytes stages in their peripheral blood while 422 (74.3%) cases were infected with ring stages only. Of the 339 P. falciparum positive blood smears, 5620 gametocytes were screened for their sex-ratio. The mean sex-ratio was 0.31 (3.22 female per male). Prevalence of gametocytaemia was significantly higher (P<0.05) in chloroquine (CQ)- resistant than in CQ-sensitive patients with days 7 and 14 follow up. The homology of variance with risk factors for gametocytes on days 7 and 14 were highly significant (P<0.001) in the study period but during the post-exposure period of days 3 and 5, these were insignificantly correlated. INTERPRETATION & CONCLUSION: A high density of P. falciparum gametocytes was observed at the time of preparation of blood slide on day 0. Improper chloroquine treatment along with poor patient compliance for radical treatment and the presence of chloroquine resistant P. falciparum malaria may have enhanced the prevalence and density of P. falciparum gametocytes which was instrumental in signaling the persistent malaria in this area.

Insecticidal activity of Valeriana jatamansi (Valerianaceae) against mosquitoes.

A root extract of Valeriana jatamansi (code BAL-O) exhibited larvicidal and adulticidal activity against different mosquito species. The median lethal concentration (LC50) of BAL-O against larvae of Anopheles stephensi, Anopheles culicifacies, Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus were 68.1, 42.8, 51.2, 53.8, and 80.6 mg/liter, respectively. The LC50 and the 90% lethal concentration against adult An. stephensi, An. culicifacies, Ae. aegypti, Ae. albopictus, and Cx. quinquefasciatus were 0.14, 0.16, 0.09, 0.08, and 0.17 and 0.24, 0.34, 0.25, 0.21, and 0.28 mg/cm2, respectively. The median knock-down time and 90% knock-down time of the fraction were 13, 13, 12, 13, and 18 and 24, 25, 21, 20, and 42 min against An. stephensi, An. culicifacies, Ae. aegypti, An. albopictus and Cx. quinquefasciatus, respectively, using 0.28 mg/cm2 impregnated papers. The median effective time and 90% effective time against An. stephensi at 4 degrees C were 46.6 and 8.7 days, and at 29 degrees C, 25.5 and 5.6 days, respectively. Gas chromatographic-mass spectrometric analysis of BAL-O showed 2-butanone,4-(2,6,6-trimethyl-2-cyclohexen-l-yl) (10.11%), patchouli alcohol (8.55%), cubenol (5.97%), caryophyllene oxide (5.46%), cadinol (5.23%), and aristolene (5.19%).

Anti-malarial activity of some xanthones isolated from the roots of Andrographis paniculata.

Four xanthones were isolated from the roots of Andrographis paniculata using a combination of column and thin-layer chromatographic methods. They were characterized as (i) 1,8-di-hydroxy-3,7-dimethoxy-xanthone, (ii) 4,8-dihydroxy-2,7-dimethoxy-xanthone, (iii) 1,2-dihydroxy-6,8-dimethoxy-xanthone and (iv) 3,7,8-trimethoxy-1-hydroxy xanthone by IR, MS and NMR spectroscopic methods. In vitro study revealed that compound 1,2-dihydroxy-6,8-dimethoxy-xanthone possessed substantial anti-plasmodial activity against Plasmodium falciparum with its IC(50) value of 4 microg ml(-1). Xanthones bearing hydroxyl group at 2 position demonstrated most potent activity while xanthones with hydroxyl group at 1,4 or 8 position possessed very low activity. In vivo anti-malarial sensitivity test of this compound on Swiss Albino mice with Plasmodium berghei infection using Peters' 4-day test gave substantial reduction (62%) in parasitaemia after treating the mice with 30 mg kg(-1) dose. In vitro cytotoxicity against mammalian cells revealed that 1,2-dihydroxy-6,8-dimethoxy-xanthone is non-cytotoxic with its IC(50) > 32 microg ml(-1).