Efficacy of Ethanolic plant extracts of Zingiber officinale, Raphanus sativus, Rosa indica and Aloe vera against Heterotermes indicola

The present study was performed to evaluate the anti-termitic potential of four common plant species of Zingiber officinale, Raphanus sativus, Rosa indica, and Aloe vera. The worker and soldier cast of H.indicola were collected from Populus euramericana, old tree, University of the Punjab, Lahore, Pakistan. The extracts of plant species were prepared using Soxhlet Extractor HR 2118 Philips grinder was used to crush dried plant material into fine powder. Different concentrations were made and 0.5 ml of each concentration was poured on filter paper and placed in petri plate (arena). In laboratory bioassay, fifty active workers of H. indicola along with five soldiers were added in each arena. The biological activity of ethanolic extracts of these plants was evaluated after 24 h until 96 h. The ethanol extract of Z. officinale caused the highest mortality (100%) while the least mortality (68%) was observed in R. indica extract. The LT50 for Copyright © 2021 The Authors. Production and hosting by Department of Life Sciences, University of Management and Technology is licensed under a Creative Commons Attribution 4.0 International License Z. officinale were 24.34, 40.40 and 64.7 h for concentrations of 10%, 5% and 3% respectively. Present findings suggested that these plant extracts can provide environmental friendly management of H. indicola. In A. vera, significant mortality was observed against the H. indicola i.e. 94%, 64% and 44% on exposure of 10%, 5% and 3% concentrations. While LT50 were 34.66, 65.59, and 100.1 hours against 10%, 5% and 3% concentrations. In R. sativus, mortality of H. indicola was 76%, 50% and 30% while LT50 against was 59.10, 86.20, and 127.3 h, against the concentration of 10%, 5% and 3%. Least mortality was observed in R. indica i.e. 68%, 44% and 30% while LT50 were 64.17, 94.58 and 125.5 h at 10%, 5% and 3% respectively. This study reports that the extracts of Z. officinale, A.vera and R. Sativus have the potential to be used for termite control especially Heterotermes indicola to minimize the damage.


Introduction
Termites have been mostly characterized by their colonial behaviour; belong to insect order Isoptera [1,2]. They are of medium size, light colour, polymorphic, soft bodied and cellulose eating insects [1,2,3]. The termites consist of more than 90 families distributes in 370 genera which was economically important to crops [4]. A total of 2650 species of termites have been reported worldwide. They are an important component of tropical and sub-tropical ecosystem [5,6].
Replacement of synthetic pesticides with that of biodegradable compound extracted from living organisms could prevent adverse effects of synthetic pesticides. To ease environmental burden, we can use plants which have high degree of diversity and provide variety of phytometabolites, some of that can be used as insecticides/ pesticides [14,15]. Plant derived products (essential oils) have been investigated for pest controlling. Plant based insecticides have been evaluated to antagonize toxic potential of chemical insecticide. Botanical pesticides are therefore environmentally safe and friendly. They have numerous advantages/ benefits over chemical insecticide being eco-friendly, biodegradable and are also effortlessly available [16].
Natural antitermitic compounds affect differently on different termite species [22,23]. Another study evaluated the toxic potential/ termicidal effect of Methanolic and Aqueous leaves extracts of Piper betle and Carcica papaya against Coptotermes curvignathus [24]. The toxic potential of Pinus roxburghii, Cedrus deodara, Tectona grandis and Dalbergia sissoo was also evaluated against H.indicola [25]. Present research was performed to evaluate the antitermitic potential of ethanolic extract of Z. officinale, R. sativus, R. indica and A. vera against Heterotermes indicola (workers and soldiers). These bioinsecticides can be used against the control of termites and will not pollute the environment, being ecofriendly.

2.1.Collection of termites & soil
Worker and soldier cast of H. indicola were collected from Populus euramericana, old tree, University of the Punjab, Lahore, Pakistan. Termites were kept for 1 week in Petri-plates along with 5 gram oven dried soil for further experimentation. Soil (sandy loam) was taken from Zoology department lawn, University of the Punjab, Lahore. This was later sieved and sterilized.
Then placed at 70°C in drying oven for removing any fungal contamination.

2.2.Extract preparation
The leaves and petals of R. indica and leaves of A. vera were taken from Botanical garden, University of the Punjab, Lahore. However Z. officinale and R. sativus were purchased.
Through washing was done using distilled water and were dried under shade for two weeks.
Extracts were prepared using Soxhlet Extractor. HR 2118 Philips grinder was used to crush dried plant material into fine powder. Powdered plant material wrapped into filter paper was placed into Soxhlet Extractor with 200 ml of absolute Ethanol. Isomantle was used for heating Ethanol. Extracts were obtained after completion of six cycles, kept in Reagent bottles from which 10%, 5% and 3% dilutions were prepared.

Anti termitic assay
Anti termitic assay was performed using [26]. The whatman 42 filter paper C were placed in each petri plate. 0.5 ml of each concentration was poured on filter paper with a micropipette. 50 active workers of H. indicola along with five soldiers were added in each Petri -plate. Readings were taken for the first eight hours and then readings were taken after 24 hours and finally up to 96 hours.

Mortality rate in percentage = Dead termites x 100
Total termites

Repellency Assay
Repellency test was performed using filter papers of 9 cm diameter and cutted into two. The one half of filter paper was exposed with 10%, 5%, 3% concentrations and considered as treated (T). The second half was considered as untreated (UT). 10 termites were released into the gap between the filter paper. Three replicates of each concentration were maintained. After 15 minutes, termite's number was count on each half of filter paper and maintains experiment till 120 minutes. To minimize effect of light, whole setup was covered with black cloth. A concentration was considered repellent if 21 or more termites (out of 30) were present on the untreated area.

Statistical analysis
Probit analysis was performed using the Statistical Software Minitab version 18 to evaluate the differences in the mortality.

Results
Highest mortality within 96 hours was recorded with Zingiber officinale extract against the termite (H. indicola) and causes death to 100% population in 10% and 5% as well. While 66% mortality was observed in 3% concentrated extract. In A. vera extract, significant mortality was also observed against H. indicola which leads to 94% mortality at 10%, 64% at 5% and 44% at 3%. In R. sativus extract, moderate was observed against the H. indicola i.e. 76%, 50% and 30% while R. indica extract causes the least mortality of 68%, 44% and 30% (Fig 1).
The LT50 were also assessed to estimate the doses with respect to time for all the plant extracts against H. indicola (Table I and respectively (Fig 2). The LT50 of R. sativus extract was 59.10, 86.20, and 127.3 h, while 64.17, 94.58 and 125.5 h were observed in R. indica at 10%, 5% and 3% concentrations (Fig 3).
The repellence test was also performs to estimate the extract efficiency against the H. indicola.
The extract was found to be repellent. The repellence between the different concentrations of each plant extracts was non-significant. The repellence between each extracts, Rosa indica show low level of repellence with respect to other three plants extracts (Table III).

Discussion
The present study was design to assess the plant extracts against the termite (H. indicola). The Z. officinale was found to be most effective on all plant species. These results are supported by the study of [27]. They reported 100% mortality of H. indicola when treated with aqueous extract of Z. officinale. Whereas our results recordings are further assisted by the findings of [28], who studied effect of Z. officinale extract on Macrotermes bellicosus and reported significant mortality and high repellency against M. Bellicosus. Z. officinale has also proved its repellent effects against whitefly (Bemisia argentifolii) [27,29].
The effect of A. vera extract against termites has been reported for the first time. Our recordings are further assisted by [30], who tested A. vera extract against Anopheles stephensi 81% mortality was recorded at 10% concentration against third instar of A. stephensi. [31] also tested the A. vera effectiveness at the concentration of 10 % against the armyworm larvae (Spodoptera frugiperda) and almost half population was eliminated. Our studied concluded that A. vera at same 10 % eliminates 94 % of H. indicola population. There is no published work on the application of R. sativus extract against termites but plant contains raphanin, which act as antibacterial and antifungal [32,33]. R. sativus extract possess antimicrobial properties against food spoilage bacteria like Listeria, Enterococcus and Micrococcus [33]. Many studies had been conducted to overcome the termite's species with the alcoholic extracts of flowering plants [34][35][36][37][38].
The repellence test was also performs to estimate the extract efficiency against the H.

Conclusion
Ethanol extracts of Z. officinale and A.vera can be used to quickly control the termite species. While, high concentrations of R. Sativus and R. indica have a potential for termite control as well. As all these extracts were found toxic against H. indicola, they are further required to be tried against other termite species of Pakistan for cost effective and environmentally friendly management.

Conflict of Interest
The author declare no conflict of interest