INTRODUCTION:

Wheat (Triticum aestivum L.) is the most important human food and is grown on more land in the world than any other crop. It is the most important food for approximately 2 billion people¹⁶. Wheat provides approximately 55% of carbohydrates and 20% of food calories consumed worldwide³.

More and more people changed their food preferences, switching from traditional foods to rice and grains¹⁷. Wheat plays an important role in our economy⁴.Approximately 25-30% of crops are destroyed every year in fields and warehouses due to different insect⁹Although there are few pests in rice, it is possible for insects to harbor pests that may cause quality/nutrition differences and a large number of losses depending on the spraying and storage time¹⁵.

Sitophilus oryzae (L.) is endemic to India and causes 18.30% loss in rice¹. The species has a short lifespan and can form large populations².

S. oryzae are small and tough in appearance and are reddish brown to black in color. Old bugs harvest and breed in stored crops. The female weevil bores several holes in the grain, but lays only one egg in one grain, filling the hole with a gelatinous liquid. Larvae feed on grain for an average of 18 to 34 days. Sitophilus oryzae larvae consume 14mg of rice per day⁵. They eat the starch and eviscerate it, leaving the outer shell intact. The sexes of Sitophilus oryzae are similar, but on closer inspection males and females can be distinguished by their price; men are shorter than women. It is reported that it flies towards the wind^8.

Wheat is the main crop of Northern Bihar. After the crops are harvested, the stored rice is attacked by insects, causing huge losses. We still rely on pesticides for pest control. The aim of this study is to examine the life history, behavior and habitat of the pest in order to effectively combat it.

MATERIALS AND METHODS:

A biological study of the rice weevil, Sitophilus oryzae was conducted as a laboratory study from July 2021 to February 2022 at Jai Prakash University, Chapra, on four different types of rice. Culture of rice weevils began by collecting adult worms from infected rice and adding them to a glass jar filled with rice. The mouth of the box was covered with a cotton cloth and young adults were identified according to rostra as reported by^6.

After identification, 10 pairs of rice worms were released into 50g rice in plastic boxes of three different sizes per box, each with a capacity of 250g, and the jars were stored in the environment. Experiments were performed in CRD and repeated three times. Provide fresh rice regularly to encourage insect development. Remove damaged grains from the bottle every morning.

Grains containing eggs were separated out by examining under binocular and were used for further studies. The pellets were carefully examined by removing them from the vial and cutting the pellets accordingly to determine the incubation time.

Larval instars are determined by the presence of moults and the width of the head capsule, as described by¹². The juvenile stage is determined by subtracting the incubation and larval stages from the total time from spawning to adulthood. The ability of S. oryzae adults to survive in the presence or absence of food was determined by separating cultured male and female adults. Both seasons followed the routine.

RESULTS AND OBSERVATIONS:

The incubation period of S. oryzae remained almost similar in various varieties of wheat as there was no significant difference among them (Table 1). The minimum Incubation period was noted on variety HUW 214(7.35days), while maximum on variety HI 8498 (9.68 days).

It was apparent from Table 1 that the minimum larval period was found in variety HUW 214(23.27), which was followed by HP 1761(24.61) days. The maximum larval period was observed in variety HI 8498(32.38 days) followed by varieties DBW 14(28.26) and K 8804 (27.08) days. There was no significant variation with regard to the pupal period among different wheat varieties. It has ranged between 11.10 to 13.98 days, being minimum in varieties HP 1761(11.10) and maximum in variety HI 8498(13.98) days (Table 1).

The data regarding developmental period showed that the total developmental period of the pest has ranged between 41.81 to 56.04 days. Longest developmental period of the pest was observed in variety HI 8498 (56.04) days which decreased in the following varieties DBW 14(50.11), K 8804(48.99), HP 1761(43.62) and HUW 214(41.81) days (Table 1).

Table 1: Different Reproductive period (days) of wheat weevil in wheat genotypes

Wheat Genotypes	Incubation period	Larval period	Pupal period	Developmental Period
DBW 14	9.05	28.26	12.80	50.11
HI 8498	9.68	32.38	13.98	56.04
HP 1761	7.53	24.99	11.10	43.62
HUW 214	7.35	23.27	11.19	41.81
K 8804	8.59	37.08	13.32	48.98

It was obvious from Table 2 that the maximum number of eggs were laid by the females on variety HUW 214 (96.75 eggs), while it was minimum on variety HI 8498 (71.21 eggs). Both these varieties were significantly different from others.

It has been depicted from Table 2 that significant higher hatchability of the pest was found in variety HUW 214 (87.03%) which was followed by HP 1761(82.08%). The minimum hatchability of the pest was observed in variety HI 8498(52.28%) which was followed by DBW 14(68.72%) and K 8804(73.23%).

Observations recorded on pupation have indicated that the minimum pupation (54.02%) was observed in variety HI 8498, which was followed by DBW 14(60.12%) and K 8804(60.32%). The maximum pupation percentage was found in variety HUW 214(76.39%) which was in descending order in HP 1761(73.12) percent (Table 2).

Table 2: Reproductive parameters of wheat weevil in different wheat genotypes

Wheat Genotypes	Fecundity (Female/eggs)	Hatchability (%)	Pupation (%)
DBW 14	80.89	68.72	60.12
HI 8498	71.21	52.28	54.02
HP 1761	87.01	82.08	73.12
HUW 214	96.75	87.03	76.29
K 8804	83.09	73.23	60.32

According to the observations shown in Table 3, it was found that the emergence of adult beetles was significantly affected in various wheat varieties. A less number of beetles were observed in variety K 8804 (59.86) which did not differ much in the HI 8498 (61.2). Highest emergence of adult beetles was found in variety HUW 214(82.38) which was followed by HP 1761 (81.65). Adult emergence in DBW 14 was observed as 62.09 percent during the research period.

Table 3: Emergence and longevity of wheat weevil in different genotypes

Wheat Genotypes	Emergence	Longevity
Wheat Genotypes	Emergence	Male	Female
DBW 14	62.09	11.38	19.98
HI 8498	61.23	10.92	15.09
HP 1761	81.65	13.28	19.15
HUW 214	82.38	13.63	20.97
K 8804	59.86	11.35	17.19

The minimum life span of S. oryzae (Table 3) male was observed on the wheat variety HI 8498 (10.92 days), which was almost same in the varieties K 8804 (11.35) and DBW 14(11.38) days. The maximum longevity of female beetles was recorded in variety HUW 214(20.97 days), which was almost same in the varieties DBW 14 (19.98) and HP 1761(19.15) days. The minimum longevity was observed in variety K 8804(17.19) days. It has been observed from the above data that the longevity of female S. oryzae varied between 15 to 21 days. The difference in male S. oryzae longevity was lesser than the female S. oryzae which has been between 10 to 13 days.

DISCUSSION:

The incubation time of rice remains almost the same and therefore does not matter. Almost similar delay data were found by^10,11. They observed the incubation period of corn (6 days), rice and sorghum (5-9 days), and rice (7-11 days) grains. The incubation period of rice worm eggs on wheat is very important for related research. The incubation period of wheat HUW 214, HP 1761 was short compared to that of HI 8498, DBW 14, which was very long. The incubation time of rice remains almost the same and therefore does not matter. Almost similar delay data were found by^10,11. They observed the incubation period of corn (6 days), rice and sorghum (5-9 days), and rice (7-11 days) grains. The incubation period of rice worm eggs on wheat is important for research. Compared with HI 8498 and DBW 14, the incubation period of HUW 214 and HP 1761 wheat was short and long.

There are significant differences between the larval stages of the rice varieties tested in this research. The maximum HI value of rice at that time was 8498(32.28) days. The difference between larval stages is important in interpreting the results of relevant studies. The shortest duration was 214(23.27) days for rice variety HP 1761(24.99) and HUW strain Sitophilus oryzae. These findings are almost identical to those obtained by¹¹ stated that the initial stages of rice germination range from 14 to 28 days.

The maximum pupal values occur on HI 8498 (13.98) and GW 1139(12.81) days, and the minimum pupal values occur on HP 1761(11.10) and HUW 214(11.19) days. ^10,11 recorded the early stages of several varieties of rice (7 days) and sorghum (5 to 8 days). The variety showed the lowest development time; HUW 214(41.81 days), followed by K 7903, 48.24 days.

According to^13, the growth period of barley varieties resistant to Sitophilus oryzae is between 29 and 38 days. The number of eggs (number of eggs laid) of female rice worms on rice grains ranged from 71.21 to 96.75. The lowest number of eggs was obtained in farm HI 8498 (71.21).¹⁴reported that females lay between 99.35 and 350.81 eggs throughout their lives. Current findings on the fertility of S. oryzae establish some correlations with the hardiness or hardiness of different rice varieties. The incubation period of rice weevil eggs in different rice varieties varies between 7.35 and 9.68 days, with HUW 214 variety having the highest hatching rate (7.35days) and HP 1761 variety having the lowest hatching rate (52.28 percent in 7.53 days.

The egg yield of different rice varieties is very different; the largest ones are HUW 214(87.03%) and HP 1761 (82.08%)^14. hatchability was found to be between 60.70% and 83.25%. The highest pupation rate was observed in HUW 214(76.39%) and HP 1761(73.12%) varieties.

The response of rice varieties to the emergence of the Sitophilus oryzae as an adult varied between 51.83% and 82.38%. HUW 214 wheat variety (82.38%) has the highest wheat variety, almost on par with other varieties such as HP 1761(81.65%) beetle. Wheat variety K 8804 recorded the lowest figure (59.86%). It is noteworthy that the presence of insects is higher in the wheat variety and less in the resistant wheat variety.¹⁴ noted that the prevalence of the disease in adults ranged from 41.05% to 48.00%.

The lifespan of male insects varies between 10.92 and 13.62 days. The HI 8498 variety has the shortest lifespan (10.92 days), while HUW 214 has the longest lifespan (13.63 days), followed by K 8804, DBW 14 and GW 1139 as 11.35, 11.38 and 11.79 days respectively^13. found that the lifespan of male Sitophilus oryzae in barley ranged from 23.13 to 35.52 days. The lifespan of Sitophilus oryzae females varies between 15.09 and 20.97 days, while the HI 8498 variety has the shortest lifespan (15.09 days) and the HUW 214 variety has the longest lifespan (20.97 days). Females of various species have been observed to live longer than males. The present findings are consistent with those obtained by^13, who found that the lifespan of the barley female beetle Sitophilus oryzae ranged from 23.66 to 39.56 days.

REFERENCES:

1. Adams JM. Weight loss caused by development of S. oryzae. J. Stor. Prod. Res. 1976; 12: 269-272.

2. Aitken AD. Insect travelers I: Coleopteran Technical Bulletin HMSO, London, United Kingdom. 1975; 31.

3. Breiman A and Graur D. Wheat evaluation. Israel Journal Plant Science. 1995; 43: 58-95.

4. Chowdhry MA, Maqbool A, Mahmood N and Khaliq I. Performance of pure and mixed stands for biomass and grain yield in Hexaploid wheat. Pak. J. Biol. Sci. 1998; 1: 145-147.

5. Giolebiowska Z. The feeding and fecundity of Sitophilus granaries (L), Sitophilus oryzae (L) and Rhizopertha dominica (F) in wheat grain. Journal of Stored Products Research. 1968; 5: 143-155.

6. Halstead DGH. External sex difference in store product coleoptera. Bulletin of Entomological Research. 1963; 54: 119-134.

7. Khalequzzaman M and Khanomi M. Effect of cypermethrin alone and in combination with leaf and seed extract of neem against adult Tribolium castaneum (Herbest). Rajshahi University Journal of Zoology. 2006; 25: 45-49.

8. Khare BP and Agrawal NS. Studies on biology of Sitophilus oryzae (Linn) and their distinguishing character in male and female. Journal of Stored Product Research. 1970; 20: 183-188.

9. Lal S and Shrivastava BP. Insect pest of stored wheat in Madhya Pradesh (India). Journal of Entomological Research. 1996; 9(2): 141-148.

10. Malagaon ME and Trochez PA (1985): Evaluation of weight loss on stored wheat caused by the lesser grain borer and observation on its life cycle under laboratory condition. Acta agronomica, 35 (4): 78-90.

11. Sattigi HN, Kulkarni KA and Thantadarya. Studies on the biology of rice weevil Sitophilus oryzae L. on wheat and Sorghum under laboratory conditions. Mysore J. Agri. Sci. 1985; 21:302-304.

12. Sharifi S and Mills RB. Radiographic studies of Sitophilus zemais (Motsh.) in wheat kernels. J. Econ. Entomol. 1971; 7: 105-106.

13. Singh DK. Studies on relative resistance/susceptibility of barley varieties to Sitophilus oryzae (L.) M.Sc. (Ag) Thesis, submitted to department of Entomology, CSAU, Kanpur. 1985.

14. Singh DK, Singh B, Singh YP, Pandey ND and Malik YP (1996): Relative resistance of some wheat and barley varieties to rice weevil, Sitophilus oryzae Linn. Indian J. Ent., 58: 280-285.

15. Singhamony S, Anees I, Chandrakala T and Osman Z. Efficacy of certain indigenous plants products as grain protectants against S. oryzae (L) and R. dominica (F). Journal of Stored Products Research. 1985; 22(10): 21-23.

16. Slafer GA and Satorre EH. An introduction to the physiological and ecological analysis of wheat yield (In: Wheat-Ecology and physiology of yield determination). Food Products Press, New York, USA. 1999.

17. World Bank. Kenya Agricultural Growth and Strategy Options. Unpublished Sector Report, Nairobi, Kenya: The World Bank. 1989.

Received on 13.04.2024 Modified on 25.04.2024

Res. J. Pharmacognosy and Phytochem. 2024; 16(2):103-106.

DOI: 10.52711/0975-4385.2024.00020