An experiment was conducted to evaluate the bio-efficacy of Lemonin [Lemon Peel Extract] LE; against sucking pests of cotton that is whitefly; thrips and jassid at Multan. The bio product Lemonin was applied when the density of all pests was above economic threshold levels. There were five treatments along with one synthetic chemical Diafenthiuron [Polo] and one control/untreated and all treatments were replicated for three times. The entire test of bio product produced significant effects.The rate of pest population of each pest was well managed by lemonin and kept the insect populations below ETL’s in comparison to chemical used as standard.
Cotton (Gossypium hirsutum L.) is one of the most important fiber and cash crop of Pakistan. Pakistan has made progress by increasing yield up to 641 Kg per hectare in 1992 – 2000 (Jiskan, 2001). Still the yield per hectare is less than many other cotton growing countries. Among a variety of reasons of low yield, the magnitude of insect pests, which damage (average 5-10 percent damage) the cotton crop from sowing to maturity, plays an important role. The severe attack of insect pests causes heavy qualitative and quantitative yield losses varying from 40-50% (Naqvi, 1976).
With the increasing trend of transgenic cotton in Pakistan, the farmers are facing problems regarding sucking pest complex for which they have to adopt intensive control methods mainly relying on chemical control.
Cotton has been worldwide challenging for pest management problems. About 1326 species of insects and mites attack cotton crop around the world. It is attacked by 145 species of insects and mites in Pakistan (Huque, 1994). Cotton jassid, Amrasca devastans (Dist.), cotton whitefly, Bemisia tabaci (Genn.), and thrips, Thrips tabaci (Lind.) are regular sucking insect pests in Pakistan. These pests require regular application of insecticides. In spite of large acreage, yield of seed cotton is very low because of severe pest complex. According to an estimate sucking pests complex cause about 20-40% yield losses in Pakistan [Ahmad 1999]. Important sucking insect pests are jassid Amarasca devastans Dist. (Hemiptera: Cicadellidae), whitefly, Bemisia tabaci (Genn.)
No single pest control method is sufficient for good production. With effective control of cotton pests, yield of cotton can be increased by 200-300 kg ha-1 [Khan et al. 1987]. Pests are main problem of agriculture that damage many crop plants. Various methods have been used to protect the crops from these natural enemies. Although using of pesticides is recognized as the most widely used method to solve this problem; however the health risks and environmental effects from their uses should be concerned (Feol et al., 2011). In traditional agriculture, the herbal pesticides are of special interest because they are biodegradable and friendly to environment (Rahman et al., 1999). Among sucking pest complex whitefly is the most notorious and key pest. Cotton whitefly (Bemisia tabaci Genn.) damages the plant in three different ways i.e., by constantly sucking the cell sap resulting in 50% reduction in boll production, by secreting honey dews on which sooty mold develops (Ahmad et al., 2002) and also acting as a vector of leaf curl virus disease (CLCuV) (Nelson et al., 1998). The average yield loss in Pakistan caused by CLCuV was reported to be 38.7 % during 1993 (Khan and Khan, 1995), which is threatening our cotton-based economy. There are different pest control tactics, but the most common and quicker one is that of chemical control which is generally adopted by our farming community.
These insect pests are mainly controlled by synthetic chemicals but because of their several ill effects, plant derivatives are being tried by the farmers. These plant derivatives are safe to man and other non target organisms and friendly to the environment. At least 46 families of flowering plants have insecticidal activities (Feinstein, 1952). Chemical control of the pests becomes imperative when all other control methods fail to control the target pests but on the other hand indiscriminate use of insecticides has not only caused the resistance problem in these pests but it has also polluted the environment along with other health hazards. (Bashir et al., 2001 & Raza and Afzal, 2000). Therefore, the judicious and effective use of bio product at proper time is most important.The present studies were conducted to evaluate the efficacy of bio product against sucking pests of cotton whitefly jassid and thrips.
MATERIALS AND METHODS
Fresh peels of lemon fruit were collected and grinded along with potassium hydroxide and water to make a Bio product. Bio product was prepared in bard-yard at NARC Islamabad. Trial was conducted on cotton field in Multan. For evaluation of bio product (lemon peel extract) experiment was conducted on cotton sown on May 25th , 2013. The plot size was 10 x 15 feet. The layout consist; of five treatments. Synthetic insecticide Diafenthiuron (POLO) was purchased from the local market. The plots were arranged in a randomized complete block design with three replications. In order to data recording; the populations of sucking pests, pre spray were recorded. Twenty plants were randomly selected from each treatment for data recording from each plot and number of pests present were visually counted and recorded and averaged to get mean population per replicate; then calibration was done; to know the amount of water required per plot. Treatments (TI, T2, T3, & T4) were sprayed @ 200ml, 300ml, 400ml and 50ml with lemonin and polo respectively lemonin; while in T5 was not sprayed left as check plot. Data was recorded after 24 & 72 hours after 1st spray. Similarly after 2nd spray the same procedure was adopted. Percent population changes (increase or decrease) were calculated using the modified Abbot’s Formula as below;
Data analysis was performed by variance and means; and used transformed averages at 5% 1% level of significance.
RESULTS AND DISCUSSIONS
Bemisia tabaci (Genn.)
The results of the present study area found that the cotton Bemisia tabaci was high and specifically damage was increased on the crop during summer season. In order to reduce the infestation level of the Bemisia tabaci on cotton through lemonin in comparison to synthetic product field condition was determined; highly significant differences among the treatments after application of bio product and the results are shown in table No. I & II. After 24 hours of 1st spray both treatments Polo Diafenthiuron @ 500ml per acre lemonin @ 400ml per acre gave significant and statistically better management of whitefly adults that is 84.29 and 84.85 respectively and managed well up-to 72 hours 78.07 & 65.07 respectively see table – I. The same managing trend of whitefly adult mortality was noticed after 2nd spray; see the table – II. Data recorded after 2nd spray of 24 hours & 72 hours show mortality 61.90% and 62.26%; while the synthetic product produced mortality 63.19% and 62.26%; which was almost equal and statistically caused more than 50% mortality.
Table – I % mortality of whitefly after 1st spray
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Table – II % mortality of whitefly after 2nd spray
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AMARASCA DEVASTANS DIST.
Lemonin produced significantly good results against cotton jassid @ 400ml which were similar to chemical Polo @ 500ml and the control spectrum remained significant till 72 hours after spray; See table III. After 2nd spray maximum reduction in jassid population was recorded in plots treated with bio product @ 400ml and synthetic chemical Diafenthiuron Polo, which were significantly different among each other. The results are presented in table IV.
Table – III %mortality of jassid after 1st spray
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Table – IV%mortality of jassid after 2nd spray
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THRIPS TABACI LIND
Lemonin gave significantly good results at all dose rates that is 200; 300 and 400ml per acre in comparison to polo used @ 500ml per acre; Lemonin @ 400ml gave 91.46 % mortality in comparison to polo Diafenthiuron @ 500ml per acre and both products managed up to 72 hours above 80%; results are depicted in table –V and after 2nd spray the control was effective in similar fashion of 1st spray; see the table – VI.
Table – V %mortality of thrips after 1st spray
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Table – VI %mortality of thrips after 2nd spray
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The results of this study show (LEMONIN) Lemon Peel Extract; excellent insecticidal properties against cotton sucking insects. Lemonin @ 400ml per acre managed all sucking insects of cotton [Whitely; Jassid & Thrips] and can be recommended for the management of cotton sucking insects and vegetables grown in home backyards for safe use and minimum toxic residues in comparison to synthetic chemicals/pesticides. As these fruits are readily available in the local markets all the year round and farmers can use the lemon peels to protect their crops. Since these materials are used in ethno-botany for the treatment of various ailments, they are safe, cheap, easily biodegradable, and technologically and environmentally friendly. They could be valuable alternatives to the synthetic insecticides for crops protection.
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BY Syeda Nasiha Seemi, M.Azhar Javaid, Faisal Nouroz