1. Introduction

Since bread, macaroni, and other baked items made from wheat are a staple in the diets of most Egyptians, wheat is a significant cereal crop that ranks first among food and strategic crops in Egypt. Likewise, wheat straw is used as animal feed [1]. The stored wheat grains are liable to be attacked by many insect pests which results in huge economic losses, leading to their loss in terms of quality, quantity, and eventual decline in market value [2]. 

Rice weevil, Sitophilus oryzae Linnaeus cause severe damage to cereal grains, through direct feeding on grain kernels. It originated from India, spread around the world by commerce and now has a cosmopolitan distribution [2]. In Egypt in particular and Africa in general, this pest is one of the most destructive insect pests of stored grain crops that causes 10-65% damage under moderate storage conditions, while it accounts for 80% under prolonged storage conditions [3]. This pest causes loss in grain weight, nutritional value decline, end use quality deterioration in addition to the low rate of seed germination [2]. In Egypt, large wheat losses of about 10-20% [4] were recorded due to the infection with this pest during long-term storage (≈six months) in government warehouses, which are locally called “Shona”. Therefore, the control of this pest is very important, and chemical control is the most important and most widely used, but the indiscriminate and uncontrolled use by farmers led to the development of resistance and thus its ineffectiveness [5].

Various methods have been developed and used to control stored pests, in particular, powders from plant sources, which have given promising results to control several Coleopteran stored pests, such as such as Callosobruchus maculatus (Fab.) [6], S. granarius (L.) [7], S. zeamais (Motsch.) [8], and Tribolium castaneum (Herbst) [9]. However, there is no information on the evaluation of Khella, A. majus (Apiaceae) and Spearmint, M. microphylla (Labiatae) leaf powders as an insecticide for S. oryzae. In light of the foregoing, the objective of this study was to assess the efficacy of powdered extracts obtained from two different species of plants: A. majus and M. microphylla in protecting stored wheat grains from rice weevil (S. oryzae) infestation to reduce the heavy loss of wheat grains in terms of quantity and quality deterioration during storage in “Shona” for a long period of about six months.

2. Materials and Methods

2.1. Insect culture

Sitophilus oryzae L. cultures were kept in a controlled temperature and humidity environment (28 ± 2 °C and 70% ± 5% RH) with 12-h cycles of light and darkness. Adults were acquired from stock cultures at the Central Agricultural Pesticides Laboratory, Agriculture Research Center, Giza, Egypt, Department of Insect Population Toxicology. The insects were given whole wheat grains as meals.

2.2. Collection and preparation of plant powders

In the El-Fayoum Governorate of Egypt, fresh leaves of Khella, A. majus (Khela, Umbelliferae, Family Apiaceae), and Spearmint, M. microphylla (Habq El bahr, Family Labiatae), were collected. They were then taken right away to the laboratory (Figure 1). Thereafter, they were washed with running water to clean them of dust. The leaves were harvested, dried for seven days at room temperature in a shady, well-ventilated area, and then powdered using an electric grinder. The powder was then sieved through a 0.5 mm mesh to ensure particle size consistency. The powders were kept at room temperature in airtight plastic containers before being used in the tests.

2.3. Laboratory experiments

To determine the effects of A. majus or M. microphylla leaf powders on adults of S. oryzae, 10 g of clean, uninfested wheat grain were combined with 2.0, 5.0, or 8.0 g of each plant powder in each plastic jar (250 mL). Powder/grain admixtures were thoroughly shaken for 15 min to ensure complete mixing homogenization. Then, 5 copulating pairs (5 males: 5 females) of newly emerged adults of S. oryzae were introduced into each cups and covered with muslin cloths. To ensure accuracy of the data, four replicates were performed for each treatment along with the control. The jars stored in conditions similar to those of rearing chamber rearing for 30 days. To estimate mortality and adult emergence were counted at 30 days after treatment as well as the grains were segregated and weighed into undamaged and insect damaged grains, the percent weight loss of wheat grains in storage was then calculated, as follows Gwinner et al. [10].

Where, WL percent weight loss, U is the weight of undamaged grains, D is the weight of damaged grains, Nu is the number of undamaged grains, and Nd is the number of damaged grains.

To assess the effects of A. majus or M. microphylla leaf powders at 8.0 g on adults of S. oryzae for 180 days (≈six months) were mixed with 10 g clean uninfested wheat grain in each plastic jar (250 mL). Powder/grain admixtures were thoroughly shaken for 15 min to ensure complete mixing homogenization. Then, 5 copulating pairs of newly emerging S. oryzae adults (5 males: 5 females) were put into each cup and covered with muslin cloths. To ensure accuracy of the data, four replicates were performed for each treatment along with the control and six groups were established. The jars were kept for six months (maximum storage period in the Shona in Egypt) in surroundings akin to a rearing chamber. At 1, 2, 3, 4, 5, and 6 months after treatment, counts of adult emergence and mortality were made. In the first set, insect emergence and mortality were measured 30 days after treatment, and the grains were weighted separately for undamaged and insect-damaged grains. Next, the percent weight loss was computed according to the method described in Gwinner et al. [10]. Thereafter, the first set of treated and untreated wheat was removed and discarded. Other groups were opened monthly, for six months (after treatment).

For the purpose of the germination test, random seed samples from each group were individually placed in Petri dishes with wet filter paper. Grains germination percentage were computed after 7 days of planting as follows:

% Germination = (Number of seeds germinated/Total number of seeds) × 100.

2.4. Statistical analysis

One-way analysis of variance was used to statistically analyse the collected data (ANOVA). The Tukey multiple range test (P ≤ 0.05) was used to determine any differences between the treatments.

3. Results

3.1. Effect of Ammi majus and Mentha microphylla leaf powders on the mortality and emergence of Sitophilus oryaze adult

The results showed the insecticidal efficacy of A. majus and M. microphylla leaf powders at 2.0, 5.0, and 8.0 g/10.0 g wheat grains, and effects varied according to plant species and dose on S. oryaze (Table 1). A. majus leaf powder at 8.0 g/10.0 g wheat grains caused 100.0% mortality to rice weevil and complete inhibited adult emergence as well as no weight losses recorded up to 30 days after treatment followed by M. microphylla leaf powder, while their effect gradually decreases by reducing the dose.

Data provided in Table 2 and Figure 2 demonstrate that A. majus and M. microphylla leaf powders at 8.0g/10.0g wheat grains demonstrated a substantial difference in mortality and emergence of adult S. oryaze compared to compare to untreated wheat grain. From 100.0 to 62.00% of weevils’ mortality, and from 36.11 to 1.23% of adults’ emergence. A. majus leaf powder was the most potent which resulted in 80.59% death and 25.51% adult emergence at the end of the six-month therapy period, M. microphylla leaf powder caused 62.00 and 36.11%, respectively. The findings demonstrated that as exposure time increased, adult weevil mortality dropped. There was a significant difference (P≤ 0.05) in wheat grain treated with A. majus leaf powder compared with M. microphylla leaf powder where A. majus had lower infection with weevils.

Table 1. Effect of Ammi majus and Mentha microphylla leaf powders at different doses on mortality, emergence of adult Sitophilus oryzae, and weight loss of wheat grains after 30 days of storage.

Means standard error (±SE) followed no significant difference (P≤ 0.05) in a by the same letter within columns   

Tukey test.

Table 2. Effect of Ammi majus and Mentha microphylla leaf powders on mortality and emergence of adult Sitophilus oryzae during different storage months.

Means standard error (±SE) followed no significant difference (P≤ 0.05) in a

by the same letter within columns   

Tukey test.

Figure 2. Effect of Ammi majus and Mentha microphylla leaf powders (8.0g/10.0g wheat grain) on Sitophilus oryzae adult mortality.

3.2. Effect of Ammi majus and Mentha microphylla leaf powders on grain weight loss and germination

Data indicated in Table 3 and Figure 3 show that leaf powder of A. majus recorded the highest germination percentage (84.09%) and the lowest weight loss (23.50%) in the treatments of wheat grain against S. oryzae, and the same trend was seen in wheat grain treated with M. microphylla leaf powder, scoring 70.04%, and 38.00%, respectively, at the end of six months of storage, while the untreated wheat grains recorded the lowest germination percentage (24.00%) with the highest weight loss (98.20%).

Table 3. Effect of Ammi majus and Mentha microphylla leaf powders on weight loss and germination of wheat grains during different storage months.

Means standard error (±SE) followed by the same letter within columns indicate no significant difference (P≤ 0.05) in a Tukey test.

Figure 3. Germination percentage affected by storage periods and infection with Sitophilus oryzae.

4. Discussion

Plant extracts as powders or essential oils are potentially value in the control of storage pests [11,12,13]. In this study, the insecticidal efficacy of A. majus and M. microphylla leaf powders in protecting wheat grains during long storage (≈six months) was investigated against the rice weevil, S. oryzae. The results showed that A. majus and M. microphylla leaf powders had insecticidal effects on weevils. These effects varied based on the plant species, time period, and dose. In line with these findings, the earlier research on powders taken from other plant species, such as Acorus calamus L. and Annona squamosal L. [14] has shown to be effective alternatives to hazardous chemicals for suppressing S. oryzae [9].

Powders of A. majus and M. microphylla were effective in protecting wheat grains from infestation because they recorded the highest mortality rate and reduced the adult emergence in treated wheat grains. Present findings line with those of Devi et al. [15]; Govindan et al. [14]; Ismail and Sleem (2021) [9] reported reduced damage of grains treated with leaf powder extracts from different plant species due to their effect on mortality and adult emergence of S. oryzae.

Leaf powders of A. majus and M. microphylla were significantly effective in protecting wheat from weevil infestation and weight loss for up to six months of storage, which is reflected in an increased percentage of grain germination than the control group, these findings concur with Govindan et al. (2020); Mehta and Kumar (2020) [14,16].

5. Conclusion

According to the findings, A. majus and M. microphylla leaf powders exhibit a wide spectrum of negative effects on S. oryzae. These powders cause severe mortality, and decreased adult emergence. In addition, this study offers evidence in favour of the leaf powders of A. majus and M. microphylla as a potential source of natural insecticides, which can also be employed as a tool to control rice weevil populations for prolonged storage periods of wheat.

Ammi majus and Mentha microphylla leaf powders protecting stored wheat grains from rice weevil (Sitophilus oryzae) infestation after 180 days (≈six months) of treatment.

Highlights

► The present work throw light on the influence of A. majus and M. microphylla powders in wheat grain at different storage periods against the rice weevil, S. oryzae L. ► Leaf powders of A. majus and M. microphylla have revealed insecticidal as well as propitious protective effect on wheat grains against weevil invasion for up to six months' storage. ► Major bioactivity against this pest is manifested by reduced the progeny and high mortality.

List of abbreviations

Not applicable.

Declarations

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article. The authors declare that there is no conflict of interest.

Authors' contributions

S.M.I. subject selection, study design, carried out the experiments, paper writing, collecting, interpretation of the data, and performing statistical analysis. The author read and approved the final manuscript.

Consent for publications

The author agrees to have read the manuscript and authorize the publicationof the final version of the manuscript

Conflict declaration

The authors declare that there is no conflict.

Conflict of interest

None of the authors have any conflict of interest to declare.

Availability of data and material

Data are available on request from the authors.

Funding/Support

Not applicable.

Ethics approval and consent to participate

Not applicable.

Acknowledgements 

Not applicable.

ORCID

https://www.orcid.org/0000-0002-4885-7383

How to cite this article: Seham Mansour Ismail*‎. ‎Efficacy of Ammi majus (Apiaceae) and Mentha microphylla (Labiatae) as Protectants of Wheat Grain Against Sitophilus oryzae L. (Coleoptera: Curculionidae). International Journal of Advanced Biological and Biomedical Research, 2023, 11(1), ‎‎‎1-9‎‎‎. Link: http://www.ijabbr.com/article_701681.html