The development of hosts that are resistant and evaluation of botanical extracts to H. armigera Hübner (Lepidoptera: Noctuidae) is crucial for sustainable management, yet very limited in Ethiopia. Therefore, this study was done to identify alternative methods to insecticide control through host consumption study and botanical extracts. The performance of third-fifth larval stages of H. armigera on three host plant varieties including chickpea, tomato and faba bean and botanical extracts against the third larval instars and oviposition deterrence was studied under laboratory condition (22°C ± 2°C, 55% ± 5% RH, 12:12 L: D photoperiod). Significant differences were found in the efficiency of conversion of ingested food (ECI%) (F = 80.06; df = 6, 2; p < 0.05) and efficiency of conversion of digested food (ECD%) (F = 175.91; df = 6, 2; p < 0.05) values of H. armigera reared on the three host plant varieties of the whole larval instars. The minimum relative consumption rate (RCR) (11.271 ± 0.328) and maximum approximate digestibility (AD) (177.9 ± 1.928) values of the whole larval instars were on Dagaga and Koshari, respectively. The values of relative growth rate (RGR), ECI% and ECD% of the whole larval instars were highest on chickpea varieties and lowest on tomato Koshari. Among chickpea varieties, Habru was relatively resistant to larval instars of H. armigera. Botanical extracts at 50% neem oil (NO), 5% birbira seed extract (BSE) and 5% neem seed extract (NSE) (18.4%) resulted superior in larval mortality however, statistically not different. At both 5% and 2.5% concentration level of botanical extracts the minimum larval mortality was recorded from neem leaf extract (NLE). Maximum numbers of eggs were laid on control treatments and the minimum eggs were on 5% BSE. The deterrent effect of 50% neem oil was stronger (ODI = 17.66%) than that of 5% BSE (ODI = 14%) which is statistically similar value with 5% NSE (ODI = 13%). In conclusion, the result indicated that use of Habru chickpea variety with 50% NO was very effective in controlling both the larvae and deterring the adults of H. armigera from egg lying. These measures could be important in the wider managements of H. armigera by integrating host resistance and botanical extracts.
Chickpea (Cicer arietinum L. (Family: Fabaceae) is one of the most important pulse crop grown in many parts of African and Asia. It is cheap source of proteins and maintains soil fertility through biological nitrogen fixation [
Seeds of the three chickpea (Cicer arietinum L.) varieties (Var. Habru, Ararti and Natoli), fababean (Vicia faba L.) varieties (Var. Dagaga, Wolki and Moti) and tomato (Lycopersicon esculentum Mill) variety (Var. Koshari) were obtained from Debre Zeit, Hollota and Malkassa Agricultural Research Centres, Ethiopia, respectively. These varieties were selected based on their preference for productions among farmers. In some area chickpea was considered as double crop especially in West Showa zone; sown after harvesting the main crop from the field. The host plants were planted in the research field of Ambo University, Main campus in September 2017.
H. armigera larvae were originally collected from chickpea unsprayed farm of Dandi district of West Showa zone, Oromiya region. The farm was located at 09˚01. 303’, latitude 038˚07. 094’ longitude and altitude 2285 m.a.s.l. The stock cultures were maintained under a laboratory condition (22˚C ± 2˚C, 55% ± 5% RH, 12:12 L: D photoperiod) on the leaves and pods of chickpea grown on the field for this purpose. Prior to the experiment the insect had been reared on respective natural hosts (chickpea, faba bean and tomato) for two generations under the above laboratory condition. The first and second larval instars of H. armigera were reared in groups of twenty onto a plastic container (17 cm diameter, 6 cm depth with ventilation windows), water-soaked cotton was fitted to ventilation window to avoid leaf drying of each host variety and the remaining third-fifth instar larvae were reared individually in a plastic vials (6 cm diameter, 6.5 cm depth) with the green pods of chickpea and faba beans and leaf/fruits of tomato varieties for a generation as previously reported procedures [
There were seven treatments. The experiment includes three varieties of chickpea, faba bean and a variety of tomato, described above. The experiment was conducted separately with third, fourth and fifth larval instars of H. armigera these larval instars were chosen because they are aggressive and can cause huge damage to the crops and they measurable than early instars. H. armigera larval instars were reared separately onto plastic vials as indicated above to prevent cannibalism. Each larval instar was provided separately with green pods of each chickpea and faba bean varieties, and fruit and leaves of tomato variety. The treatment was laid out using completely randomized design with three replications. There were 50 larvae per replication for each instar.
The data on food utilization, weight gain and feces produced were collected following the method of [
Relative Consumption Rate ( R C R ) = E A × T (1)
Relative Growth Rate ( R G R ) = P A × T (2)
Approximate Digestibility ( A D ) = ( E − F E ) × 100 (3)
Efficiency of Conversion of Digested Food ( E C D ) = ( P E − F ) × 100 (4)
Efficiency of Conversion of Ingested Food ( E C I ) = ( P E ) × 100 (5)
where, A = mean dry weight of insect over unit time (mg), E = dry weight of food consumed (mg), F = dry weight of feces produced (mg), P = dry weight gain of insect (mg) and T = duration of feeding (days).
The data from the whole instar larvae were used to construct a dendrogram line for cluster comparison of the seven treatments.
The seeds A. indica were collected from Malkassa Agricultural Research Center and and leaves were collected from Adama town, 98 km from Addis Ababa. The seeds of M. ferruginea were collected from Ambo University. These collected plant materials were brought to Ambo Plant Science laboratory in December 2017. These botanicals were prepared following the procedures developed by [
The extracted botanicals were prepared at 5% concentration by dissolving 5 kg of botanical seed or leaf powder in 100 liters of water to spray one hectare (
S/N | Treatments | Treatment descriptions |
---|---|---|
1 | 5%NLE | 5% water extract of A. indica leaf |
2 | 5% NSE | 5% water extract of A. indica seeds |
3 | 50% NO | 50% oil extract of A. indica seeds |
4 | 5% BSE | 5% water extract of M. ferruginea seeds |
5 | 2.5% NLE | 2.5% water extract of A. indica leaf |
6 | 2.5% NSE | 2.5% water extract of A. indica seeds |
7 | 2.5% BSE | 2.5% water extract of M. ferruginea seeds |
8 | UC | Untreated (control) treated with dH2O |
9 | SCH | Control treated with the standard synthetic Deltamethrin 25% E C at recommended rate |
The rates of crude botanical extracts were estimated by using the following formula (Equation 6);
C = W V × 100 (6)
where; C = percent concentration of botanicals, W = Weight of solute (botanicals), V = Volume of solution (volume of botanical + volume of solvent (water)
There were seven treatments and two controls, as described in
Larval mortality was recorded starting immediately after treatment applications. Larvae are assumed to be dead when not responding to touch. Based up on the percent larval mortality of each treatment, four botanical extracts were selected to evaluate oviposition deterrence against adult moth of H. armigera via no-choice oviposition test. The treatments were 5% water extract of A. indica leaf, 5% water extract of A. indica seeds, 50% oil extract of A. indica seeds, 5% water extract of M. ferruginea seeds, and untreated control. The treatment were arranged in completely randomized design and replicated three times. A newly hatched pair of moth, (one female and one male moth), from the stock populations were placed into oviposition cages (30 × 30 cm). A single planted chickpea (variety Habru) on plastic pot (20 cm top, 13.5 cm bottom and 20 cm length) 65 - 70 days old were sprayed with the help of hand pressurized sprayer with 30 ml of each treatment when they are at 25% flowered. The treated chickpea pot were kept at room temperature until the applied treatments be dried. Then, after we confirmed the confinement of the paired moths within the oviposition cages, each treated potted chickpea plant was placed inside the cages separately. After 24 h, evaluations on the number of eggs laid on each treatment were conducted and oviposition deterrent indices (ODI) were calculated following [
O D I = 100 ( C − T ) C + T (7)
where, C and T are the mean number of eggs laid on control and treated leaves, respectively.
Prior to analysis, the nutritional indices parameters were checked for normality by Kolmogorov-Smirnov method. The parameters were analysed with one-way ANOVA using SAS statistical software to determine the similarities or differences. Statistical differences among the means were evaluated using the LSD test at 5% level of significance. The data of whole larval instars were used for cluster analysis which was done using SAS software by Ward’s method. Data on percent larval mortality, number of eggs laid and oviposition deterrence were log-transformed before analysis and analysed with a one-way ANOVA. Differences among treatments were determined with a Tukey test.
There were significant differences among values of the relative consumption rate (F = 34.57; df = 6, 2; p < 0.0001), relative growth rate (F = 8.25; df = 6, 2; p < 0.0006), efficiency of conversion of digested (F = 485.21; df = 6, 2; p < 0.0001) and ingested (F = 310.85; df = 6,2; p < 0.0001) food, and approximate digestability (F = 47.39; df = 6, 2; p < 0.0001) of different host varieties to nutritional indices of the third larval instars (
With regard to RGR, higher values (0.2233 ± 6.66 - 0.21160 ± 0.006) were observed on chickpea varieties, whilst the lowest was recorded from larvae fed on Koshari, this was not significantly different with the values of Wolki and Moti faba bean varieties. Higher (6.737 ± 0.073 - 6.800% ± 0.115%) ECI value was
Hosts | Varieties | RCR | RGR | ECI (%) | ECD (%) | AD (%) |
---|---|---|---|---|---|---|
Chickpea | Ararti | 3.450 ± 0.05c | 0.2250 ± 0.002a | 6.737 ± 0.073a | 9.7 ± 0.057a | 17.33 ± 0.88e |
Habru | 3.420 ± 0.06c | 0.21160 ± 0.006ab | 6.800 ± 0.115a | 9.0 ± 0.057b | 22.67 ± 1.45de | |
Natoli | 3.403 ± 0.146c | 0.2233 ± 6.66a | 6.767 ± 0.088a | 9.033 ± 0.145b | 23.67 ± 2.603d | |
Faba bean | Dagaga | 5.600 ± 0.264a | 0.2007 ± 0.005bc | 3.367 ± 0.088bc | 4.167 ± 0.088d | 38.33 ± 2.401b |
Wolki | 5.133 ± 0.185ab | 0.1847 ± 0.003cd | 3.067 ± 0.133c | 5.167 ± 0.068d | 39.67 ± 0.666b | |
Moti | 4.990 ± 0.105b | 0.1913 ± 0.112cd | 3.600 ± 0.057b | 5.167 ± 0.240c | 31.67 ± 2.026c | |
Tomato | Koshari | 3.567 ± 0.22c | 0.1817 ± 0.005d | 2.567 ± 0.176d | 3.033 ± 0.088e | 53.67 ± 1.766a |
The means followed by different letters in the same columns are significantly different (LSD, P < 0.05, LSD); RCR, relative consumption rate; RGR, relative growth rate; ECI (%), efficiency of conversion of ingested food; ECD (%), efficiency of conversion of digested food; AD (%), approximate digestibility.
recorded from the varieties of chickpeas and 9.7% ± 0.057% was the maximum value of ECD recorded from Ararti followed by Habru and Natoli. Whereas, the lowest values of both ECI (2.567% ± 0.176%) and ECD (3.033% ± 0.088%) were on Koshari. The third instar larvae reared on Koshari had the highest (53.67% ± 1.766%) AD value (
The highest values of ECI (7.550 ± 0.149 - 7.797% ± 0.118%) and ECD (38.40 ± 0.737 - 40.33% ± 1.766%) of the fourth instar of H. armigera were on Ararti, Habru and Natoli varieties, there was statistically no difference on these varieties with regard to the fourth larval instars. While, the lowest (4.973% ± 0.188%) ECI and ECD (15.89% ± 0.053%) was from Koshari variety. Maximum (66.73% ± 0.733%) of AD were recorded from Koshari and the minimum (33.52% ± 0.289%) was from Moti which is similar with the value of Wolki (
There were significant difference with regard to RCR (F = 57.96; df = 6, 2; p < 0.001), RGR (F = 3.10; df = 6, 2; p = 0.0451), ECI (F = 36.02; df = 6, 2; p < 0.001), ECD (F = 138.22; df = 6, 2; p < 0.001) and AD (F = 606.37; df = 6, 2; p < 0.0001) values of the fifth larval instar of H. armigera (
Hosts | Varieties | RCR | RGR | ECI (%) | ECD (%) | AD (%) |
---|---|---|---|---|---|---|
Chickpea | Ararti | 4.587 ± 0.059d | 0.7083 ± 0.036a | 7.790 ± 0.095a | 38.44 ± 0.345a | 38.66 ± 0.357c |
Habru | 4.177 ± 0.090e | 0.6893 ± 0.032a | 7.797 ± 0.118a | 40.33 ± 1.766a | 40.37 ± 0.316b | |
Natoli | 4.383 ± 0.441de | 0.6303 ± 0.057a | 7.550 ± 0.149a | 38.40 ± 0.737a | 39.22 ± 0.276bc | |
Faba bean | Dagaga | 5.633 ± 0.066b | 0.6800 ± 0.055a | 6.300 ± 0.115bc | 24.27 ± 0.442b | 35.34 ± 0.654d |
Wolki | 5.267 ± 0.120c | 0.5903 ± 0.047ab | 5.873 ± 0.150c | 24.81 ± 0.452b | 34.18 ± 0.416de | |
Moti | 5.133 ± 0.088c | 0.6213 ± 0.040a | 6.567 ± 0.296b | 24.60 ± 0.452b | 33.52 ± 0.289e | |
Tomato | Koshari | 7.067 ± 0.233a | 0.4807 ± 0.062b | 4.973 ± 0.188d | 15.89 ± 0.053c | 66.73 ± 0.733a |
The means followed by different letters in the same columns are significantly different (LSD, P < 0.05, LSD); RCR, relative consumption rate; RGR, relative growth rate; ECI (%), efficiency of conversion of ingested food; ECD (%), efficiency of conversion of digested food; AD (%), approximate digestibility.
Hosts | Varieties | RCR | RGR | ECI (%) | ECD (%) | AD (%) |
---|---|---|---|---|---|---|
Chickpea | Ararti | 0.03144 ± 4.058c | 0.3147 ± 0.036b | 22.68 ± 0.277a | 50.75 ± 0.456a | 29.47 ± 0.357c |
Habru | 0.02863 ± 6.212d | 0.3337 ± 0.032b | 22.70 ± 0.344a | 53.24 ± 2.326a | 31.18 ± 0.316b | |
Natoli | 0.03004 ± 3.019cd | 0.3927 ± 0.057b | 21.99 ± 0.434a | 50.60 ± 0.973a | 30.03 ± 0.276bc | |
Fababean | Dagaga | 0.03760 ± 4.451b | 0.3430 ± 0.055b | 18.35 ± 0.336bc | 32.04 ± 0.584b | 26.15 ± 0.654d |
Wolki | 0.03579 ± 0.001b | 0.4327 ± 0.049b | 17.10 ± 0.438c | 32.74 ± 0.562b | 24.99 ± 0.416de | |
Moti | 0.03518 ± 6.045b | 0.4017 ± 0.040b | 19.12 ± 0.862b | 32.47 ± 0.596b | 24.33 ± 0.289e | |
Tomato | Koshari | 0.04717 ± 0.0015a | 0.5423 ± 0.062a | 14.48 ± 0.547d | 20.98 ± 0.070c | 57.55 ± 0.733a |
The means followed by different letters in the same columns are significantly different (LSD, P < 0.05, LSD); RCR, relative consumption rate; RGR, relative growth rate; ECI (%), efficiency of conversion of ingested food; ECD (%), efficiency of conversion of digested food; AD (%), approximate digestibility.
Compared to other varieties the lowest (ECI; 14.48% ± 0.547%, ECD; 20.98% ± 0.070%) values were recorded on Koshari from which the highest (57.55% ± 0.733%) value of AD was recorded (
With regard to the value of nutritional indices of the whole larval instars (third to fifth) of H. armigera on the seven varieties, there were significant difference among the values ECD (F = 175.91; df = 6, 2; p < 0.05), ECI (F = 80.06; df = 6, 2; p < 0.05) and AD (F = 215.2; df = 6, 2; p < 0.05) (
The highest (1.248% ± 0.002%) was recorded on Ararti variety; statistically similar value with Natoli and Habru whereas, the lowest (1.205% ± 0.005%) was from Koshari which is on par with Moti and Wolki values for RCR. Among the varieties tested, maximum (36.30 ± 0.605 - 37.30% ± 0.415%) for ECI and (98.13 ± 1.772 - 102.57% ± 4.053%) for ECD was recorded from larvae reared on Habru/Ararti/Natoli varieties and followed by faba bean varieties. The lowest (ECI = 22.02% ± 0.887%; ECD = 39.91% ± 0.072%) for Koshari. Furthermore,
Hosts | Varieties | RCR | RGR | ECI (%) | ECD (%) | AD (%) |
---|---|---|---|---|---|---|
Chickpea | Ararti | 8.068 ± 0.108c | 1.248 ± 0.002a | 37.21 ± 0.443a | 98.89 ± 0.857a | 85.5 ± 1.391e |
Habru | 7.625 ± 0.057c | 1.239 ± 0.006ab | 37.30 ± 0.415a | 102.57 ± 4.053a | 94.2 ± 0.951bcd | |
Natoli | 7.817 ± 0.102c | 1.246 ± 6.639a | 36.30 ± 0.605a | 98.13 ± 1.772a | 92.9 ± 2.754cd | |
Faba bean | Dagaga | 11.271 ± 0.328a | 1.224 ± 0.005bc | 28.01 ± 0.430bc | 60.47 ± 0.978b | 99.8 ± 3.602b |
Wolki | 10.436 ± 0.319b | 1.208 ± 0.003cd | 26.04 ± 0.486c | 62.69 ± 1.050b | 98.8 ± 1.246bc | |
Moti | 10.159 ± 0.062b | 1.214 ± 0.011cd | 29.29 ± 1.143b | 62.23 ± 1.287b | 89.5 ± 2.430de | |
Tomato | Koshari | 10.681 ± 0.319ab | 1.205 ± 0.005d | 22.02 ± 0.887d | 39.91 ± 0.072c | 177.9 ± 1.928a |
The means followed by different letters in the same columns are significantly different (LSD, P < 0.05, LSD); RCR, relative consumption rate; RGR, relative growth rate; ECI (%), efficiency of conversion of ingested food; ECD (%), efficiency of conversion of digested food; AD (%), approximate digestibility.
the highest (177.9% ± 1.928%) value of AD was determined from Koshari and the lowest (85.5% ± 1.391%) was from Ararti, but similar value with Moti of the whole instar larvae of H. armigera (
The result of the dendrogram showed three distinct clusters labelled as A (sub clusters A1 and A2), B (sub clusters B1 and B2) and line C. Cluster A included subclusters A1 (Habru); A2 (Natoli and Ararti), whereas cluster B included B1 (Moti); B2 (Dagaga and Wolki) and Line C consisted of Koshari (tomato) indicating that Habru (Chickpea) and Moti (Faba bean) as intermediate group, Koshari as partially resistant line to the larvae of H. armigera (
There were significant differences between treatments (F = 11.45, df = 8, p < 0.0001) in causing mortality to the third larval instar of H. armigera (
Compared to botanical extracts, high larval mortality was achieved when treated with A. indica oil extract at 50% (50%NO), M. ferruginea at 5% (5% BSE) and A. indica seed extract gave similar results, followed by leave extracts of A. indica at 5%. Similarly, there were significant differences between treatments (F = 7.88, df = 4, p = 0.0059) in affecting number of eggs laid by the female moths (
In no choice experiment there were significant differences between treatments (F = 45.21, df = 4, p = 0.0001) in deterring the oviposition of H. armigera moth adults (
The deterrent effect of 50% A. indica oil extract (50% NO) was stronger (ODI = 17.66%), followed by 5% M. ferruginea (5% BSE) seed extract (ODI = 14%) and A. indica seed and leaf extract at 5% concentration (5%NSE) (ODI = 13%). The least deterrent effect was when treated by 5% A. indica leaf extracts (
H. armigera is a highly polyphagous destructive pest insect of many economically crucial crops [
integrated pest management programs for any crop plant resistance to pests [
demonstrated that, there was a difference among the nutritional indices parameters of the different varieties tested on larval instars of H. armigera. The variation in the value of nutritional indices observed among varieties in the present finding may dependent on the durations of larval feeding periods and protein content of the host plants used for the experiment. Previously research output stated, low protein content in host plants/diet can cause an increase in the rate at which the larvae feed [
It has been postulated that ECI is a general index of an insects ability to use the food consumed and may vary with the digestibility of food and the proportional amount of the digestible portion of food which is converted to body mass and metabolized for energy needed for vital activity like growth and development [
The ECI and ECD values showed an increased trend from third to fifth instar in most cases. An increasing of ECI and ECD values from the third to fifth larval instar indicated a higher efficiency of the conversion of ingested and digested food to body biomass. Increases in ECD from early to late instars were reported by [
The cluster analysis represented here indicated that grouping within each cluster might be due to a high level of physiological similarity of different varieties of the same host plants or due to variability in physiological characters of the varieties clustered. Line C (Koshari) was the least suitable and subcluster A2 which consists of Natoli and Ararti was the most suitable varieties for H. armigera and followed by A1 (as an intermediate for chickpea variety; Habru), B2 (Wolki and Dagaga) and B1 (as an intermediate for fababean variety; Moti). This result is related to the finding of [
This study demonstrates that A. indica oil extract at 50% (50%NO) is effective in causing high larval mortality. The high larval mortality in oil (50%) could be due to high concentration of azadirachtin in the seeds of A. indica. High larval mortality of H. armigera due to seed extracts of A. indica was reported by [
In conclusion studying nutritional indices of insects leads to better understanding of insect behaviour and physiological activities, in turn host variations, host suitability, resistance and it gives direction towards development of integrated pest management of H. armigera. ECI and ECD values of the H. armigera larval instars were the highest on chickpea followed by faba bean varieties. The larvae fed on the tomato Koshari variety had the lowest value of ECI and ECD, which suggests that these larvae were apparently not as efficient in turning digested food into biomass. The result for cluster analysis indicated chickpea variety Habru as an intermediate for resistance against H. armigera. Incorporation of botanical extracts either locally extracted or commercially available M. ferruginea at 5% seeds and A. indica oil extract at 50% (50%NO) extracts were effective in causing larval mortality and deterring the oviposition capacity of the adult by altering the subsequent population of H. armigera. Hence, the use of Habru chickpea variety with 50% (50%NO) extracts were effective in managing the larval and adult stages of H. armigera. This finding can be applied to design a comprehensive IPM strategy to H. armigera in major hosts. Future research has to focus on the use of host plant resistant and botanical extracts as it has receiving emphasise as a part of integrated pest management tools due to its economic feasibility, eco-friendly and social acceptance of the tactic.
This study was supported by the USAID Feed the Future IPM Innovation Lab, Virginia Tech, Cooperative Agreement No. AID-OAA-L-15-00001. Tarekegn Fite is an icipe student supported by the USAID Feed the Future IPM Innovation Lab, Virginia Tech, under the provision of Rice, Maize, and Chickpea IPM Project for East Africa. We also gratefully acknowledge the financial support by the UK’s Department for International Development (DFID); Swedish International Development Cooperation Agency (Sida); the Swiss Agency for Development and Cooperation (SDC); and the Kenyan Government. The views expressed herein do not necessarily reflect the official opinion of the donors. We also wish to forward our thankful appreciation to Plant Science Laboratory Technicians of Ambo University, College of Agriculture and Veterinary sciences for technical support especially Mr. Fula’a Galana and Mr. Habtamu Haile.
No potential conflict of interest was reported by the authors.
Fite, T., Tefera, T., Negeri, M., Damte, T. and Sori, W. (2018) Management of Helicoverpa armigera (Lepidoptera: Noctuidae) by Nutritional Indices Study and Botanical Extracts of Millettia ferruginea and Azadirachta indica. Advances in Entomology, 6, 235-255. https://doi.org/10.4236/ae.2018.64019