RESUMO
One of the key reasons for the poor performance of natural enemies of honeydew-producing insect pests is mutualism between ants and some aphid species. The findings demonstrated that red wood ant, Formica rufa Linnaeus (Hymenoptera: Formicidae) had a deleterious impact on different biological parameters of the lady beetle, Hippodamia variegata Goeze (Coleoptera: Coccinellidae). H. variegata laid far fewer eggs in ant-tended aphid colonies, laying nearly 2.5 times more eggs in ant absence. Ants antennated and bit the lady beetle eggs, resulting in significantly low egg hatching of 66 per cent over 85 per cent in ant absent treatments. The presence of ants significantly reduced the development of all larval instars. The highest reduction was found in the fourth larval instar (31.33% reduction), and the lowest in the first larval instar (20% reduction). Later larval instars were more aggressively attacked by ants than earlier instars. The first and second larval instars stopped their feeding and movement in response to ant aggression. The third and fourth larval instars modified their mobility, resulting in increased ant aggression towards them. Adult lady beetles were shown to be more vulnerable to ant attacks than larvae. However, H. variegata adults demonstrated counterattacks in the form of diverse defensive reaction behaviours in response to F. rufa aggression.
Assuntos
Formigas , Besouros , Larva , Animais , Formigas/fisiologia , Besouros/fisiologia , Besouros/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia , Afídeos/fisiologia , Agressão , Feminino , Simbiose , Oviposição , Comportamento PredatórioRESUMO
Given the economic importance of cucurbits and the losses incurred by fruit fly infestation, the population dynamics of fruit flies in cucurbit crops and the influence of abiotic parameters, such as temperature, relative humidity, rainfall, and total sunshine hours per day on the fruit fly population were studied. The study was carried out at six locations; in district Srinagar the locations were Batmaloo, Shalimar, and Dal, while in district Budgam the locations were Chadoora, Narkara, and Bugam (Jammu and Kashmir, India). Various cucurbit crops, such as cucumber, bottle gourd, ridge gourd and bitter gourd, were selected for the study. With regard to locations, mean fruit fly population was highest (6.09, 4.55, 3.87, and 3.60 flies/trap/week) at Batamaloo and Chadoora (4.73, 3.93, 2.73, and 2.73 flies/trap/week) on cucumber, bottle gourd, ridge gourd, and bitter gourd, respectively. The population of fruit flies was significantly correlated with the minimum and maximum temperature. The maximum species diversity of fruit flies was 0.511, recorded in Chadoora. Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) was the most predominant species in both Srinagar and Budgam, followed by B. dorsalis (Hendel) and B. tau (Walker), while B. scutellaris (Bezzi) was found only in Chadoora. Results of the present investigation may be utilized in developing a sustainable pest management strategy in the agroecological system.
Assuntos
Cucurbitaceae , Herbivoria , Tephritidae , Animais , Biodiversidade , Índia , Dinâmica Populacional , Tempo (Meteorologia)RESUMO
To better understand the elicitor induced defense in wine grapes against Drosophila suzukii (Matsumura), two varieties, Pinot Noir and Chardonnay, were sprayed with jasmonic acid (JA) and salicylic acid (SA). Total phenols, total flavonoids, total tannins and total soluble sugars were quantified. Oviposition preference by D. suzukii in response to JA and SA applications were also studied. Behavioral response of D. suzukii to various sugars was recorded. The effect of flavonoids (gallic acid, catechin, quercetin at 100 and 500 ppm) on mortality of D. suzukii was also studied in CAFE assay. Our results showed that JA and SA application significantly affected phenol, flavonoid and tannin contents of grapes. Reduced injury was observed in treated plants; this reduction was more pronounced in Chardonnay than Pinot Noir. The number of eggs laid by D. suzukii females was lower in JA and SA-treated plants; this reduction was more pronounced under no-choice conditions than under choice conditions. In prandial behavior, sucrose solution (5%), glucose solution (5%), fructose solution (5%), sucrose (5%) + yeast (5%) solutions and yeast solutions (5%) showed higher attraction of D. suzukii females compared to control treatments. Among flavonoids, catechin (100 ppm) showed higher mortality of D. suzukii than rest of the treatments. The results of this study can be used for developing management strategies of D. suzukii in wine grapes and related crops.
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Jammu & Kashmir and Ladakh are two union territories (UT's) famous for their beauty and cool climate. Both the UT's are familiar with their horticulture production at the national and international level. Jammu & Kashmir offers enough scope for cultivation of all types of horticulture crops covering various sub-tropical fruits like mango, guava, citrus, litchi, temperate fruits like apple, pear, peach, plum, apricot, almonds, cherry, and apricot. Horticulture has emerged as a fast-growing sector in Jammu & Kashmir and to some extent in Ladakh, offers a wide range of opportunities to farmers for crop diversification. Horticulture has proved its credibility in improving income through increased productivity, creating employment, and strengthening exports. Jammu & Kashmir comprises 20 districts and Ladakh two districts, and both having comparative advantages in some specific types of fruit cultivation due to variations in soil fertility, soil matter, topography, and variable to harsh weather. In this survey, we analyze the district wise contribution and improvement of horticulture production of fresh fruits and an increase in their growing area. The survey-based on secondary data sources collected from the Directorate of Horticulture of Jammu & Kashmir and Ladakh. The data is analytical and empirical, directly contributing to the horticulture production of India. The area and production of apple are maximum in district Baramulla, a temperate region of J&K. While, maximum area as well as the production of apricot is in district Leh, a high altitude and cold arid region of Ladakh.
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Chlorpyriphos is one of the major organophosphorus pesticides used widely to control a range of insect pests across several crops. This insecticide is hazardous to the environment and toxic to mammals, thus, it is essential to remove the same from the environment. Similarly, use of polythene is also increasing day by day. Therefore, it is highly important to identify ways to degrade chlorpyriphos and other pesticides from the environment. We studied the degradation of chlorpyriphos and polyethylene by Citrus mealybug (Planococcus citri) bacterial endosymbionts such as Bacillus licheniformis, Pseudomonas cereus, Pseudomonas putida and Bacillus subtilis. This investigation revealed that bacterial endosymbionts use the polythene as a source of carbon and solubilize them by their enzymatic machinery. The degradation of polyethylene by endosymbionts showed a significant reduction in weight of polyethylene sheet after 15, 30 and 45 days of treatment. The SEM images showed localized degradation of the polyethylene around the bacterial cells in the biofilm. Further, the tensile strength (percentage elongation) was significantly reduced after 45 days of incubation. The weight of paraffin wax showed significant reduction in B. cereus. A significant reduction in total amount of chlorpyriphos in soil was observed at an interval of 7, 14 and 21 days after treatment by the bacterial isolates. Among the bacteria, B. cereus and P. putida were found to be most effective. The results from this study show that endosymbionts can be significantly implicated in degrading chlorpyriphos and polyethylene from the environment.
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Codling moth (Cydia pomonella, Lepidoptera: Tortricidae) is a quarantine pest of apple in Ladakh, India. We report Cydia pomonella granulovirus from infected larvae of codling moth for the first time in India. The two CpGV isolates were identified as (CpGV SKUAST-1 and CpGV SKUAST-2) and published in Genbank under accession number, MK801791 and MK801792, respectively. The mortality of CpGV was evaluated against 3rd instar larvae of codling moth at various concentrations viz., 102, 104, 106, 108, 1010, 1012 and 1014 OBS/ml. The median lethal concentrations (LC50 and LC90) were observed at 7.08 and 28.56 OBS/ml, respectively. In field, the infection rate by CpGV was 5.95 to 15.65%. Based on typical infection symptoms on the larvae, morphological features under the microscope and sequence results of the amplified product confirmed the first occurrence of CpGV from India. Thus, CpGV will form an important non-chemical strategy for managing this pest.
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The theory of coevolution suggests that herbivores play an important role in the diversification and composition of plant communities. A prevalent idea holds that grasses and grazing animals participated in an evolutionary "arms race" as grassland ecosystems started spreading across the continents. In this race, besides other things, silicification in the form of phytoliths occurred in the grasses, and the graminivorous herbivores responded through specialized mandibles to feed on plants rich in phytoliths. It is important to understand whether these mandibles equip the herbivores in different environments or the grasses can augment their defense by channelizing their energy in high resource milieu. Here we used rescuegrass (Bromus catharticus; Family: Poaceae), an alien species of South America, to understand the mechanism of resistance offered by this species against a local insect herbivore (Oxya grandis; Family: Acrididae), graminivorous grasshopper, in different silicon-rich environments. We used different concentrations of silicon and observed the types of phytoliths formed after Si amendments and studied the effect of phytoliths on mandible wear of the grasshopper. Silicon concentrations increased ca. 12 fold in the highest supplementation treatments. The results reveal that higher foliar silica concentration in Si-rich plants did not result in changing the morphology of the phytoliths; still the leaf tissue consumption was lower in higher Si treatments, perhaps due to mandibular wear of the grasshoppers. The study opens a new dimension of investigating the role of Si amendments in reducing herbivory.
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Background: In recent years, Médecins Sans Frontières has observed high mortality rates among hospitalized infants in Pakistan. We describe the clinical characteristics of the infants admitted between 2013 and 2016 in order to acquire a better understanding on the risk factors for mortality. Methods: We analyzed routinely collected medical data from infants (<7 months) admitted in Chaman and Dera Murad Jamali (DMJ) hospitals. The association between clinical characteristics and mortality was estimated using Poisson regression. Results: Between 2013 and 2016, 5,214 children were admitted (male/female ratio: 1.60) and 1,178 (23%) died. Days since admission was associated with a higher risk of mortality and decreased with each extra day of admission after seven days. The first 48 hours of admission was strongly associated with a higher risk of mortality. A primary diagnosis of tetanus, necrotizing enterocolitis, prematurity, sepsis and hypoxic-ischemic encephalopathy were strongly associated with higher rates of mortality. We observed an annual peak in the mortality rate in September. Conclusions: The first days of admission are critical for infant survival. Furthermore, the found male/female ratio was exceedingly higher than the national ratio of Pakistan. The observed seasonality in mortality rate by week has not been previously reported. It is fully recommended to do further in-depth research on male/female ratio differences and the reasons behind the annual peaks in mortality rate by week.
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Hospitalização , Enterocolite Necrosante , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Paquistão , Estudos Retrospectivos , Estações do Ano , SepseRESUMO
Efficacy of the combined treatment of a neem oil formulation and endosulfan on feeding and midgut enzyme activities of Helicoverpa armigera larvae was studied. The antifeedant activity was recorded at 24 h after treatment and the activities of midgut digestive (total serine protease and trypsin) and detoxifying (esterase and glutathione-S-transferase) enzymes were estimated at 72 h after treatment. The antifeedant activity in endosulfan + neem oil formulation (endosulfan 0.01% and neem oil formulation 1% at 1:1 ratio) was 85.34%, significantly greater than in individual treatments. Midgut digestive enzymes and EST activities were significantly reduced and the GST activity significantly increased in the combined treatment of endosulfan + neem oil formulation, thus showing increased effect of the combined treatment of the two pesticides. These results suggest that neem oil can be used in combination with endosulfan to reduce its quantity.
RESUMO
Plants respond to herbivory through various morphological, biochemicals, and molecular mechanisms to counter/offset the effects of herbivore attack. The biochemical mechanisms of defense against the herbivores are wide-ranging, highly dynamic, and are mediated both by direct and indirect defenses. The defensive compounds are either produced constitutively or in response to plant damage, and affect feeding, growth, and survival of herbivores. In addition, plants also release volatile organic compounds that attract the natural enemies of the herbivores. These strategies either act independently or in conjunction with each other. However, our understanding of these defensive mechanisms is still limited. Induced resistance could be exploited as an important tool for the pest management to minimize the amounts of insecticides used for pest control. Host plant resistance to insects, particularly, induced resistance, can also be manipulated with the use of chemical elicitors of secondary metabolites, which confer resistance to insects. By understanding the mechanisms of induced resistance, we can predict the herbivores that are likely to be affected by induced responses. The elicitors of induced responses can be sprayed on crop plants to build up the natural defense system against damage caused by herbivores. The induced responses can also be engineered genetically, so that the defensive compounds are constitutively produced in plants against are challenged by the herbivory. Induced resistance can be exploited for developing crop cultivars, which readily produce the inducible response upon mild infestation, and can act as one of components of integrated pest management for sustainable crop production.