Feasibility study on hexacopter UAV based sprayer for application of environment-friendly biopesticide in guava orchard

Aim: To study the feasibility of hexacopter UAV based sprayer for application of environment-friendly biopesticide in guava orchard. Methodology: Field experiments were conducted in Punjab (India) during 2020. UAV was evaluated for spraying environment-friendly bio-pesticidein guava orchard. UAV was operated at 2.0 m height above the tree top.The water and oil sensitive papers were fixed on the outer side as well as inside of selected guava trees at four different canopies. Organic neem seed kernel based azadirachtin 0.15% EC biopesticide was used at recommended dose. After spraying, all water and oil sensitive papers were collected for further laboratory analysis. All spray quality parameters, i.e., coverage (%), droplet density (droplets cm-2), droplet size (µm) and uniformity coefficient were determined. For the efficacy of drone sprayer insects were counted before and 1, 2, 7 days after spray (DAS) and reduction in number of insects was calculated. Results: The on-flight field capacity of spraying with UAV was 3.0-3.3 ha h-1 whereas actual field capacity was found to be 2.0-2.3 ha h-1. The total mean coverage area was found in the range of 2.67-10.67%. The maximum coverage was at the top canopy (inner and outer) of tree which was significantly higher than all other observation points on the canopy. The mean droplet density was found in the range of 14.67-28.33 droplets cm-2. The highest droplet density (28.33 droplets cm-2) was found at the top outer side of the tree canopy. The volume median diameter was found in the range of 208.0-418.3 µm whereas, number median diameter was in the range of 138 to 269 µm. The percent reduction in aphid population 1, 2 and 7 days after spray (DAS) was 38.06, 68.28 and 62.69%, respectively whereas it was 47.95, 78.69 and 70.90% with knapsack sprayer. Interpretation: Hexacopter UAV sprayer is effective in terms of quality of spray and effective control of aphid population.

Population Dynamics and Yield Loss Assessment for Pea Aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), on Lentil in Morocco

Pea aphid (Acyrthosiphon pisum Harris) is the major insect pest of lentil in Morocco. We investigated pea aphid mean numbers and yield losses on three lentil varieties at one location during three successive cropping seasons during 2015–2018. The effects of several weather factors on pea aphid population dynamics were investigated. Population density increased in early spring followed by several peaks during March–April and then steeply declined during the late spring. Aphid populations peaked at different times during the three years of the study. In 2016, higher populations occurred during the second and third weeks of April for Abda and Zaria varieties with averages of 27 and 28 aphids/20 twigs, respectively. In 2017, higher populations occurred on the 12th and 13th standard meteorological weeks (SMWs) for Zaria with averages of 24.7 and 27.03 aphids/20 twigs, respectively. In 2018, the population peaked for all varieties at three different times, 11th, 13th, and 17th SMW, with the highest for Zaria being 26.00, 47.41, and 32.33 aphids/20 twigs. Pea aphid population dynamics changed with weather conditions. The number of aphids significantly and positively correlated with maximum temperature, but significantly negatively correlated with relative humidity and wind speed. The minimum temperature and rainfall had non-significant correlations. Pea aphid infestation resulted in losses of total seed weight for all lentil varieties, with the highest avoidable losses for Bakria being 12.51% followed by Zaria with 7.72% and Abda with 4.56%. These losses may justify the development of integrated management options for control of this pest.

Modeling of aphid complex and its associated natural enemies in rapeseed-mustard in relation to climatic factors

Effect of climatic factors on population build-up of aphid complex of rapeseed-mustard viz. mustard aphid, Lipaphis erysimi (Kaltenbach), cabbage aphid, Brevicoryne brassicae (Linnaeus), and green peach aphid, Myzus persicae (Sulzer) and associated natural enemies (coccinellids, syrphids and a parasitoid, Diaeretiella rapae M’Intosh) was studied at Experimental Farm of CSK HPKV Palampur over a period of three years. Correlation coefficients indicated that the temperature favoured build-up of aphid population and their natural enemies while rainfall exerted negative impact. The population of coccinellids was negatively correlated with the population of L. erysimi and M. persicae while, positive correlation with B. brassicae was observed. On the other hand, population of syrphids was found to be positively correlated with aphid population. Predictive model using stepup regression analysis revealed that a weak relation in aphid population was attributed by weather parameters particularly minimum, maximum temperature and bright sunshine hours. Regression analysis revealed that 89 per cent variation in parasitization by D. rapae was attributed by minimum and maximum temperature, rainfall, relative humidity and bright sunshine hours.

Produs nou biorațional pentru combaterea dăunătorilor în spaţii protejate

The article presents the results of pesticidal activity study of product elaborated on the neem oil base. Bioassays were performed on aphids and spider mites in order to compare the pesticidal activity of new preparative form NEEM-01 with that of the commercial biorational products Pelecol and MatrinBio. The product NEEM- 01at a dose of 10 l/ ha has potential as aphicide and acaricide, although in terms of efficacy in controlling aphids and mites it is different. NEEM-01 was quite effective against the aphid population compared to spider mites, which are more mobile, ceasing to feed on the treated leaf. A higher mortality of pests with higher biological efficacy of NEEM- 01 was achieved after two treat-ments with an interval of 10 days between them. The results are preliminary, the research continues.

Field Evaluation of some Molecules for Management of Brevicoryne brassicae Linnaeus in Cauliflower, Brassica oleracea L var botrytis

The present study was conducted at Research Farm of ICAR- Research Complex for Eastern Region, Patna, Bihar during rabi 2020-21. Eight insecticides were evaluated against aphid, Brevicoryne brassicae in cauliflower and found that all insecticidal treatments were significantly superior over untreated control, in reducing the population of aphid however; significant differences existed among the various treatments. Flubendiamide20% WG @ 0.4gm/l was found most effective followed by lufenuron 5.4% EC @ 1ml/l and others showed intermediated effects in reduction of aphid population. The least effective treatments were neem oil and diafenthiuron in reducing the population of B. brassicae.

Application of UV-C Irradiation to Rosa x hybrida Plants as a Tool to Minimise Macrosiphum rosae Populations

UV-C irradiation is known to enhance plant resistance against insect pests. In the present study, we evaluated the effects of low doses of UV-C on Macrosiphum rosae infesting greenhouse rose (Rosa x hybrida) plants. The application of 2.5-kJ/m2 UV-C irradiation on rose leaves before infestation induced anti-herbivore resistance and negatively affected the aphid fecundity. No eggs and first instar nymphs were recorded on irradiated leaves, whereas an average of 4.3 and 2.7 eggs and 6.7 and 14 first instars were recorded on vars. “Etoile Brilante” and “Arlen Francis” untreated leaves, respectively. UV-C irradiation reduced the aphid population from naturally infested rose plants by up to 58%. In a greenhouse pot trial (GPT) in 2019, UV-C irradiation minimised the initial aphid population six hours after treatment. UV-C elicited host resistance and, also, helped in aphid repulsion without killing the adult individuals. UV-C did not affect the physiological responses of rose plants. The net CO2 assimilation of the UV-C irradiated plants ranged between 10.55 and 15.21 μmol/m2. sec for “Arlen Francis” and between 10.51 and 13.75 μmol/m2. sec for “Etoile Brilante” plants. These values, with only a few exceptions, were similar to those recorded to the untreated plants.

Chitosan Pesticides for Control Aphids (Aphis craccivora) on High Population in Long Bean (Vigna sesquipedalis) Cultivation

Pesticides with chitosan as an alternative are still relevant for aphids which are important pesticides in vegetable crops. This research was conducted to see the effect of several types of pesticides with chitosan active ingredients, the concentration of pesticides, and interactions between types of pesticides and concentrations of aphids on long bean plants. The study used factorial methods with randomized block designs. The first factor was the type of pesticide made from chitosan, which consisted of control (JO), pure chitosan (Jl), soft guard (J2), super biovit (13). The second factor was the concentration of pesticides that consisted of 0.1% (Kl), 0.3% (K2), and 1% (K3). There were 48 experimental units consisting of 12 treatment combinations and 4 replications. Data were analysed using Analysis of variance (ANOVA), and comparison between averages using Duncan Multiple Range Test (DMRT). The results showed the effect of the treatment was single or there was no interaction between the types of pesticides made from chitosan with an active concentration in all parameters of observation. Furthermore, the effect of the type of pesticide with active chitosan was significantly different only on the average aphid population I and 3 days after the first application. Whereas pesticides made from active chitosan soft guard type tended to control the aphid population higher than other types of pesticides, then the effect of pesticide concentration was not significantly different from all parameters. However, the concentration of 1% indicated to inhibit the population of aphids higher than other concentrations. The high early aphid population, the behaviour of aphid colonies, the application method, and the nature of the active ingredient of chitosan were thought to be factors that reduce the ability of pesticides to control aphids on long bean plants.

Effects of different mulches and net house on crucifer aphid (Brevicoryne brassicae L.) population, growth and yield of broadleaf mustard (Brassica juncea)

Crucifer aphid, Brevicoryne brassicae, is a key pest of broadleaf mustard and other crucifers. An alternative integrated management approaches are recommended to keep the pest below economic threshold level. A field experiment was carried out to evaluate the effect of mulching and net house on aphid population, growth and yield of broadleaf mustard. Experiment was carried out in randomized complete block design with four replications from September to December 2016 at Rampur, Chitwan, Nepal. Five treatments used in experiment was untreated control, black plastic mulch only, reflective plastic mulch only, black plastic mulch plus imidacloprid 70 WSG @ 0.13gm/liter, and net house plus black plastic mulch. The results showed that the lowest population of crucifer aphid was recorded inside the net house with black plastic mulch and black plastic mulch with imidaclorpid 70 WSG @ 0.13g/L spray. Reflective plastic mulch was superior as compared to black plastic mulch and control to reduce the aphid population. Similarly, the highest yield (26.86t/ha) was obtained inside the net house with black plastic mulch followed by black plastic mulch with imidacloprid spray (25.99 t/ha). But the benefit-cost ratio was the highest (4.09) in black plastic mulch with imidacloprid spray followed by reflective plastic mulch (3.42), black plastic mulch (3.32), and net house with black plastic mulch (3.10). Benefit-cost ratio was lower in net house with black plastic mulch but products are safe from toxins and potentially profitable in long run. Considering its ecological cost, the use of pest exclusion net is recommended as a viable option for controlling insect pests of broadleaf mustard.

Influence of ecological parameters on the incidence aphid population in different potato (Solanum tuberosum L.) cultivars

In a field trial, thirteen potato cultivars were evaluated for the incidence of aphids, Myzus persicae (Sulzer) and Aphis gossypii Glover (Aphididae: Hemiptera) during rabi seasons from 2015-2016 to 2017-2018 at District Seed Farm, Department of Agriculture, Burdwan, West Bengal. Results revealed that initiation of aphid population was noticed in the crop field on or before 51st meteorological standard week (3rd week of December) with the peak at 7th MSW (3rd week of February). However, the level of aphid population was not similar in all the potato cultivars. Though the aphid population in all the cultivars decreased gradually after the peak, the attainment of a higher population differs over the duration. In general, a positive significant correlation of aphid populations was recorded with maximum, minimum temperature, and bright sunshine hours while maximum and minimum humidity had a negative correlation. Stepwise multiple regression analysis revealed that maximum temperature had a significant influence on population fluctuation of aphid. Besides, collective influence (61.8% to 76.5%) of all the abiotic factors on the aphid population was also recorded from adjusted R2 (0.618 to 0.765) in different potatocultivars.

Effects of strip intercropping of canola with faba bean, field pea, garlic, or wheat on control of cabbage aphid and crop yield

The impacts of intercropping of canola (Ca) with faba beans (Fb), field peas (Fp), garlic (G), or wheat (Wh) were evaluated on the cabbage aphid, Brevicoryne brassicae (Linnaeus, 1758), natural enemies and canola yields in row ratios of 3Ca : 3Fb, 3Ca : Fp, 3Ca : 3G, and 3Ca : 3Wh in 2018 and 2019. In both years, the lowest aphid population was recorded in 3Ca : 3G. In 2018, the aphid population was significantly (P < 0.05) lower in 3Ca : 3Fp than in the monoculture, while, in 2019, it was lower in the intercrops compared to the monoculture. Furthermore, none of the intercrops, except 3Ca : 3Fb, showed a significant increase in the predator diversity and parasitism rate. The dry seed weight loss was higher in the monoculture and 3Ca : 3Wh than in the other intercrops. Based upon the obtained results, decreasing the density of the cabbage aphid and increasing the canola yield by intercropping canola with the faba bean, the field pea or garlic is possible with this system. The inferences of these outcomes, which are associated with the integrated pest management (IPM) in canola cropping systems, are discussed.