Management of onion seed worm ( Helicoverpa armigera ) associated with onion seed crop in Swat valley of Khyber Pakhtunkhwa

Current research work was conducted during 2016 in Swat, Khyber Pakhtunkhwa to evaluate the efficacy of synthetic insecticides (Furadan-3G and Thimet-5G), botanical extracts (Azadirachta indica and Parthenium hysterophorus) and Trichogramma chilonis (Tricho-cards) in comparison with control against onion budworm in onion seed crop, Allium cepa. The statistical design used for experiment 1 was Randomized Complete Block with 3 treatments having 3 replications, whereas 2 experiment was consisted of 4 treatments and 3 replications. In experiment-1, the lowest mean number of larvae of H. armigera was recorded in Furadan (0.48 plant) followed by Thimet (0.50 plant) and the highest was recorded in control plot (0.56 plant). In experiment-2 the lowest means number of larvae plant was recorded in Trico-cards (0.56) followed by A. indica (0.59) and Parthenium (0.61) whereas the highest were noted in control (0.75). The highest thousand seed weight (8.00g) was obtained from Furadan treated plot followed by Thimet (7.00g) and control (1.67g) respectively. Significantly lowest seeds plant was noted in control (618.8) which was statistically at par with Parthenium (812.7). The highest average yield was recorded in Furadan (521.00 kg/ha) followed by Thimet (512.00 kg/ha), Tricho-cards (475.33 kg/ha) and control (330.00 kg/ha). The maximum biological efficacy was reported in Furadan (36.00 %) followed by Parthenium (18.67 %). In lab research it was recorded that both Neem 5% and Parthenium 7% were safe for Trichogramma chilonis. The use of Neem and Parthenium in combination with bio control agent is recommended for the IPM program.


Introduction
Onion, Allium cepa (Amaryllidaceae: Asparagales) is a biennial and cross-pollinated herbaceous winter vegetable [1].There are different shapes, colors and tastes of onion.Bulbs of onion are flattened or torpedo in shape with red, yellow or white in color; It is used on daily basis in large amount [2].It is a good source of micro-nutrients such as minerals, salts and vitamins [3].Onion is the second largest vegetable in terms of world annual production after tomatoes [4].Overall onion production in Pakistan during 2014-15 was recorded as 1,763.0thousand tons on area of 135.1 thousand hectares.Similarly, onion production in Khyber Pakhtunkhwa in 2014-15 was recorded as 185.5 thousand tons on total area of 11.4 thousand hectare, in which the contribution of district Swat was 93.5 (000, tons) with an area of 3.8 thousand hectares respectively [5].The onion crop is attacked by numerous pest species including insects as well as micro-organisms (Bacteria, Fungi and viruses) [6].However, among all pest species the most devastating and threatening pest are onion thrips (Thrips tabaci) and onion budworm, (Helicoverpa armigera) [7].Onion budworm is very active pest during the flowering stage which badly affects seed portion of the crop [8].Similarly, H. armigera mostly attacks the fruiting part of the plant and also attack on the flowers and leaves of the plant as well.The adult moth of the budworm is characterized by fast, low level of flight takes an irregular path and eventually skip to other nearby plants.Forewings of Bud worms are attractive light brown while the hind wings are pale and have black scraps at the end.The female laid white spherical eggs singly at the top of plants with the size of about (0.5mm).The eggs turn darken before hatching and hatched after seven days when they are laid.Caterpillars development is temperature dependent and full feed in about seven weeks, after the full maturity, they come down to the ground from plant and pupate in the soil [9].Synthetic insecticides are being used efficiently against several insect pests but it has a lot of serious health and environmental problems [10].Continues use of synthetic insecticides, produce a range of negative effects like effects on human health, toxic to non-target organisms and widespread environmental contamination, lead to a thorough search for natural enemies for the control of insect pest [11]

Preparation of neem seed extract
For preparation of neem seed extract the experimental procedure of [16] was followed with some modification.500 g of Neem seed (500 g) were dried and crushed with the help of grinder and was soaked in 1 liter of water (1 liter).After 24 hours the obtained solution was filtered from muslin cloth.The final filtrate was considered as a stock solution.From this stock solution further desired concentration were obtained by the following formula; C1V1=C2V2 Where: V1 = Volume to be taken from stock solution to make the desired concentration C1 = Concentration of stock solution V2 = Required volume C2 = Required concentration Preparation of Parthenium hysterophorus extract Parthenium leaves were dried in micro-wave oven and were crushed with the help of grinder.The crushed powder was weighed and was soaked in known amount of distilled water for 24 hour.After 24 hours the solution was filtrate from muslin cloth and the final filtrate was considered as stock solution and the desired concentration was prepared from the stock solution [16].

Synthetic insecticides
Both the insecticides, Furadan product of FMC United @8kg /acre and Thimet product of swat agro chemicals @8 kg /acre were bought from the local market in granules form.These granules were applied before earthing up for the onion bulb.

Tricho-cards
Tricho-cards were taken from SCRI Mardan and were applied @ 4 card/acre after flowering when infestation occurred

Experiment 3
The study was conducted to find out the effect of Neem @ 5% and parthenium @ 7% extracts on T. chilonis under laboratory conditions.For that purpose, the methodology of [19] was followed with some modifications.Complete randomized design (CRD) was used and treatments were replicated five times.A filter paper (10 cm in length; 1 cm width) was dipped in the given concentration along with control (Water) for 30 second and was dried for 60 mints and placed in Petri dish.T. chilonis card ware subjected to each petri dish containing 5 eggs, and for food source to the inner side of each petri dish a honey streak honey solution was applied.

Data collection
The data were collected on the mean mortality of the natural enemy after 24, 48, 72 and 96 hours interval.

Statistical analysis
Randomized Complete Block Design was used for conducting the experiment including three replications.Data were examined by the Statistical software (Statistix 8.1).Analysis of variance was constructed and Least Significant Difference (LSD) test was carried out for the comparison of means.
For lab experiment the analysis of variance Statistix 8.1 was used under randomized completely design (CRD) and means were separated at 5% level of probability.

Results
To evaluate the effect of synthetic insecticides (Furadan, Thimet) and plant extracts (Neem 5% and Parthenium 7%) along with a biological control agent (T.chilonis) against the onion bud worm H. armegira, a research work was conducted in Agriculture Research Institute Mingora Swat during 2016.The results are as followed; Effect of different chemical treatments on mean population of Onion bud worm larvae Data in table 1 revealed that after 24 hours the highest mean number of onion bud worm larvae were noted in control plots (0.44) which was non-significant to Thimet (0.41) while showed significant difference to Furadan (0.39).The 48 hour data showed that Furadan (0.43) and Thimet (0.45) were significantly different from control plot (0.51) similar treatment effect on larvae of onion bud worm was recorded after 72 hour and 96 hours.Data recorded after 120 hours showed that lowest means number of onion bud worm were recorded in Furadan (0.47) which showed significant difference to Thimet (0.52) and control plot (0.57) while the treatment effect of week 1 was also similar to treatment effect of 120 hours.The data collected after week 2 revealed that lowest mean number of onion bud worm were noted in plot treated with Furadan (0.60) followed by Thimet (0.63) and Control (0.67).The overall mean data showed that lowest mean number were recorded in plot treated with Furadan (0.48) which showed significant difference to Thimet (0.50) and control (0.56).

Effect of different treatments on mean population of Onion bud worm larvae
Table 2 data shows mean number of larvae per plant after the application of different treatments.After 24 hours the lowest mean number of larvae per plant was noted in Neem treated plot (0.48) which showed statistically no significant difference (P>0.05) with Parthenium (0.49) and Trichocards (0.52).The highest mean numbers of larvae were recorded in control (0.60) which was statistically significant from rest of treatments.After 48 hours the lowest mean number of larvae was recorded at Neem (0.52).The highest no of larvae were observed at control (0.64) followed by Tricho-cards (0.56) and Parthenium (0.53).Data recorded after 72 hours revealed that treatment Tricho-cards (0.46) had the lowest mean number and significantly different from rest of treatments.The control showed maximum number of larvae per plant (0.69), while the remaining treatment showed no significant difference with each others.Data recorded after 96 hours indicated that the control (0.74) has highest number of larvae which showed significant difference from rest of treatments.The minimum number of larvae per plant (0.51) were noted in Trichocards followed by Neem (0.57) and Parthenium (0.60).Data recorded after day 120 hours revealed that significantly maximum mean number of larvae were noted in control plot (0.81) while the remaining treatment showed no significant different amongst each other.Similar treatment effect was recorded after week 1.Data collected after week 2 showed that control were nonsignificant to Parthenium while showed a significant difference from rest of treatments whereas the parthenium was found nonsignificant to Tricho-cards (0.71) and Neem (0.74.Mean data (overall) showed that the lowest mean numbers of larvae were recorded in Tricho-cards (0.56), followed by Neem (0.59) and Parthenium (0.61) which were statistically at par with each other.The highest mean numbers of larvae were recorded in control plot (0.75).

Effect of different treatments on yield parameters
Table 3 data revealed that the highest thousand seed weight (8.00 g) was obtained from Furadan.The treatment Tricho-cards (6.33 g) is statistically at par with Thimet (7.00 g) and Neem (4.67 g) and parthenium (4.00 g).The lowest thousand seed weight was recorded in control plot (1.67 g).The plant height data stated that maximum plant height was observed in Furadan (77.20 cm) which is significantly different from the rest of treatments followed by Tricho-cards (71.80 cm), Thimet (71.17 cm) and Neem (68.10 cm).The lowest plant height were recorded in parthenium (65.57cm) followed by control (61.80 cm).Data regarding number of seeds per umbel showed that significantly lowest seeds per plant were noted in control (618.8)followed by parthenium (812.7) and neem (890.8).The maximum numbers of seeds per umbel were noted in plot treated with Furadan (1132.0)which showed no significant difference with Thimet (1059.1)and Tricho-cards (1047.9).Yield data showed that the highest total yield were noted in Furadan (521.00 kg/ha) which was statistically at par with Thimet (512.00 kg/ha) followed by Tricho-cards (475.33 kg/ha), Neem (425.33 kg/ha) and parthenium (397.33 kg/ha) whereas the Tricho-cards showed no significant difference with Neem, Furadan and Thimet whereas, significantly different from parthenium.The lowest total yield was noted in control plot (330.00 kg/ha).

Biological efficacy of different treatments against onion bud worm larvae
Data presented in table 4 showed percent biological efficacy of different treatments.Means of all the treatments were calculated and subjected to Abbot Formula.The highest biological efficacy (36.00 %) was recorded in Furadan followed by Thimet (33.33 %) which is in close proximity with Furadan.The lowest percent biological efficacy over control was shown by parthenium (18.67 %) which was significantly different from Furadan, these were followed by treatment Neem (21.33 %) and Tricho-cards (25.33 %).

Discussion
Over all mean data showed that the lowest mean numbers of larvae were recorded in Furadan (0.48) that was not significantly different as compared to Thimet (0.50).The average mean number of larvae showed that Tricho-cards (0.56), Neem (0.59) and Parthenium (0.61) were statistically at par with each other.The highest mean numbers of larvae were recorded in control plot (0.75).Our current findings are in line with [20] who used different treatments for the control H. armigera and reported that insecticides were more effective followed by neem seed extract.Seven different chemicals were evaluated by [21] for the management of H. armigera in chick pea crop and found chemical insecticide indoxacarb 14.5 SC @ 0.5 ml/l the most productive in managing the H. armigera larval population and obtain maximum yield which also support our findings.The outcome of our research work was in contrast with [22] who observed Furadan less effective against sucking pest.Our findings are strongly supported by [23, 24].Effectiveness of botanical extracts also reported by [25] in managing pest of tomato crop.The significance of neem seed kernel extract due to its repellency or antifeedants were also previously report by [26] and concluded that it's due to the deterency of neem plant extracts to insect pests.Our findings are supported by [27] they reported the bio extracts efficacy lasts up to 10 days.Outcomes of [28] are in contrast with our findings who evaluate botanicals efficacy for the control of Helicoverpa armigera and non target natural enemies in Chickpea (Cicer arietinum L) and found NSKE effective.Efficacy of neem based extracts against Helicoverpa armigera on sunflower crop reported by [29] and observed that the biopesticides gradually reduced H. armigera population as compared with synthetic insecticides.Our results are also supported by [30] who applied different chemicals against H. armigera and reported Tracer (Spinosed @ 60 ml) effective in field as well as in laboratory as compared to Arrive.The natural enemies Trichogramma chilonis egg parasitoid showed fluctuation in management of the pest at different time interval but were significantly better after week 2 compared with control.Management techniques for the control of H. armigera reported by [31] and suggested that all the strategies in integrated form were effective.The treatment Trichogramma along with Habrobracon hebetor was fruitful and control about 97 % followed by endosulfan which control was about 75%.Numerous management strategies determined by [32] for management of H. armigera and sort out that all the management strategies were better than control.They find out all the strategies effective in comparison with control plot.Trichogramma @ 16 cards having 400-500 eggs per card in sugar cane crop at different location tested by [17] and reported significant results of controlling the pest and pest damage reducing.Botanical extract Parthenium hysterophorus also proved effective in managing the pest population and showed significant differences with other treatments.The treatment P. hysterophorus showed significant difference with control plot at 2 nd week but statistically at par with rest of treatments.

[17]. Biological efficacy (Biological efficacy determination of selected treatments)
2. Number of seed per flower of plant 3. Thousand seed weight 4. Plant height 5. Total yield per plot.

Table 5 . Mean mortality of Trichogramma chilonis in Parthenium and Neem concentrations at different time interval
Effects of neem extracts on beneficial insects in greenhouse culture.Proc USDA Workshop, USDA, ARS, ARS-86, Beltsville, MD pp 100-5.37. Mehmood, N (2016).M. Sc (Hons).In vitro management of the diamondback moth (Plutella xylostella) through different concentrations of Parthenium and Neem extracts.Uni Agri Pesh pp 22.