Egypt. J. Plant Prot. Res. Inst. (2020), 3 (1): 123 - 129 Egyptian Journal of Plant Protection Research Institute www.ejppri.eg.net Efficacy of two plant oils and their mixture on two species of Tetranychus spp. (Acari: Tetranychidae) Heba, M. Nasr; Wafaa, M. Gaber and Hala, E. Moafi Plant Protection Research Institute, Agricultural Research Center, Dokki, Giza, Egypt. ARTICLE INFO Abstract: Article History The biological effects of ginger oil (Zingiber Received: 23/ 1/ 2020 officinale), castor oil (Ricinus communis) and their Accepted: 30/ 3/2020 mixture were studied under laboratory conditions against Keywords adult female of carmine spider mite Tetranychus Tetranychus spp., cinnabarinus (Boisduval) and the two spotted spider mite Tetranychidae, ginger Tetranychus urticae Koch. (Acari: Tetranychidae). Also, oil, castor oil and LC50 of each treatment was established and the obtained laboratory conditions results revealed that the mixture of ginger and castor essential oils was the most effective in the two species. Ginger oil was more effective than castor oil which has very low effect on the two species. LC50 was 322.54, 682.65 and 17305.99 ppm for the mixture, ginger oil and castor oil, respectively, for T. cinnabarinus. However, the LC50 was 429.71, 1517.39 and 23587 ppm for the mixture, ginger oil and castor oil, respectively, for T. urticae. The results indicated that, the essential plant oils were more effective on T. cinnabarinus than T. urticae. Introduction The environmental problems biodegradable pesticides to solve the caused by overuse of pesticides have problem of long term toxicity to been the matter of concern for both mammals and, on the other hand, one scientists and public in recent years. It must study the environmental friendly has been estimated that about 2.5 million pesticides and develop techniques that tons of pesticides are used on crops each can be used Natural products are an year and the worldwide damage caused excellent alternative to synthetic by pesticides reaches $100 billion pesticides as a means to reduce negative annually. The reasons for this are impacts to human health and the twofold: (1) the high toxicity and non- environment.one of the most important biodegradable properties of pesticides natural products is essential oils (Koul et and (2) the residues in soil, water al., 2008). resources and crops that affect public The move toward green chemistry health. Thus, on the one hand, one needs processes and the continuing need for to search the new highly selective and developing new crop protection tools 123 Nasr et al., 2020 with novel modes of action makes contain a mixture of several active discovery and commercialization of substances which exert different natural products as green pesticides an mechanisms of action as a rule and thus attractive and profitable pursuit that is may be able to effectively prevent the commanding attention. Essential oils are emergence of resistant pest populations defined as any volatile oil(s) that have (Rattan, 2010 and Pavela, 2014). Ginger strong aromatic components and that give (Zingiber officinale) is a perennial and distinctive odor, flavor or scent to a plant. rhizome producing plant that is known to Essential oils are usually obtained via contain resins and a volatile oil (Zahir et steam distillation of aromatic plants, al., 2011). The castor bean Ricinus specifically those used as fragrances and communis (Euphorbiaceae) has shown a flavorings in the perfume and food great potential as a source of insecticidal industries, respectively, and more molecules against several insects (Rossi recently for aromatherapy and as herbal et al., 2010), including species of medicines. Spodoptera (Ramos-López et al., 2012). Red spider mites, Tetranychus spp. The two spotted spider mite (Acari: Tetranychidae) are associated Tetranychus urticae Koch (Acari: with more than 120 host plants of Tetranychidae) is the most economically economic importance worldwide, important plant feeding mite pest in the including cotton, strawberry, ornamental world, it attacks broad range of crops. plants, deciduous fruit trees, tomato, Due to its wide host range, its high eggplant, and other vegetables, with a reproductive capacity and its ability to wide distribution in different parts of the rapidly develop resistance to pesticides, world (Çakmak and Demiral, 2007). Red hence T. urticae is difficult to control. To spider mites can complete their life cycle reduce these negative effects, alternative from egg to adult in one to two weeks methods for the control of T. urticae are under favorable conditions (Bolland and being tested, including the use of Valla, 2000 and Biswas et al., 2004). essential oils. Essential oils are promising Commercially available synthetic agents for the control of agricultural acaricides are usually expensive and may pests. be needed to be imported for use by The present work was aimed to farmers. They also tend to have evaluate the biological aspects of ginger detrimental effects on the environment oil and castor oil and their mixture and can be hazardous to humans. These against two species of Tetranychus. negative effects have resulted in an Materials and methods increasing interest for natural plant-based 1.Rearing mites: pesticides which are assumed to be safer T. urticae and Tetranychus than the synthetic pesticides (Yanar et al., cinnabarinus (Boisduval) (Acari: 2011). Natural plant extracts play an Tetranychidae) were collected from increasingly prominent role as unsprayed castor bean plants and reared alternatives to synthetic pesticides due to at 25± 2° C and 60± 5%RH. the increasing concern on health hazards, 2.The tested plant oils: environmental pollution and negative - Ginger oil and castor oil were effects on non target organisms (Sharma bought from Essential oil et al., 2006 and Habashy et al., 2015). Extracts Center, National Moreover, botanical insecticides usually Research Center. 124 Egypt. J. Plant Prot. Res. Inst. (2020), 3 (1): 123- 129 - Ginger oil, is extracted from 4.Toxicity test: fresh ginger roots, primarily The toxicity of ginger oil, castor consisting of zingiberene (An oil and their mixture was evaluated et al., 2016) against adult females of T. cinnabarinus and T. urticae.Thirty newly emerged adult females were transferred to the lower surface of castor leave discs (2.5 cm diameter) placed separately on moist cotton wool in Petri dishes. Each petri dish contains three replicates, ten (An et al., 2016) individuals in each replicate. Each - Castor oil is extracted from castor acaricide had four concentrations which beans and consisting primarily of were sprayed on the individuals. ricinoleic acid (Thomas, 2005). Mortality was recorded for 7 days after treatment. The mortality percentage was estimated and corrected according to the Abbott’s formula, 1925. LC50 values were determined using probit analysis statistical method of Finney, 1971. Equation: Sun, 1950 (to Ricinoleic acid formula (Thomas, determine LC50 index) 2005) - Mixture of the oils made by adding proportion of 1:1 of each essential plant oil. 3. Preparing the stock solution the Results and discussion tested plant extracts: 1. Bio efficacy of ginger plant oil, Convenient stock concentrations castor plant oil and their mixture on of each plant oil were prepared on basis adult female of carmine spider mite of the tested plant weight and the volume Tetranychus cinnabarinus (Boisduval): of the distilled water (w/v) in the The data in Table (1) presence of tween 80(0.1%) as demonstrated that, the mixture of ginger emulsifier. The stock concentrations were and castor oils caused the highest kept in glass stoppered bottles and stored mortality proportion on T. cinnabarinus under refrigeration. Such stock solutions in all tested concentrations. Then, the were prepared periodically. Four diluted ginger oil caused high mortality concentrations for each plant oil were proportion. While castor oil caused very used to draw the LC-P lines. Three low mortality proportion. These results replicates were used for each agreed with Isidia et al. (2010) who concentration. proved that ginger oil has high toxic effect on cowpea insects. 125 Nasr et al., 2020 Table (1): Corrected mortality % of carmine spider mite Tetranychus cinnabarinus treated C andہ with ginger, castor oils and their mixture under laboratory conditions 25±2 60±5% RH. Conc. Mortality after treatments % Total Treatments (ppm) One day Three days Five days Seven days Mortality % 1000 26.67 13.33 10 6.67 56.67 5000 33.33 13.33 20 3.33 70 Ginger oil 10000 40 20 13.33 6.67 80 15000 43.33 20 16.67 6.67 86.67 1000 ----- 6.67 ----- 3.33 10 5000 13.33 ----- 3.33 3.33 20 Castor oil 10000 20 3.33 6.67 6.67 36.67 15000 23.33 13.33 10 6.67 53.33 1000 30 23.33 6.67 10 70 Mixture of 5000 46.67 20 16.67 ----- 83.33 ginger and 10000 70 13.33 10 ----- 93.33 castor oils 15000 70 16.67 10 ----- 96.67 However, Table (2) and Figure (1) lowest value was 0.740 followed by indicated that, the mixture of ginger and 0.962 and 1.16 for the mixture and castor castor oils was more effective than each oil, respectively. Also, the obtained essential oil alone against T. results proved that, castor oil alone has cinnabarinus with LC50: 322.54 ppm. weak effect on T. cinnabarinus but when Also, ginger oil alone was effective with added to ginger oil to form mixture, it LC50: 682.65 ppm, but castor oil was not increases its toxicity against pests. Abd effective and LC50: 17305.99 ppm. The Allah and Marouf, 2015 proved that the toxicity index was 100% for the mixture mixture of two plant extracts was more while it was 47.25&1.86 for ginger oil effective in toxicity than each extract &castor oil, respectively. The slope alone. values indicated that , ginger oil had the Table (2): Efficacy of ginger and castor oils and their mixture against Tetranychus cinnabarinus.