*4.1.2 Rice weevil (*Sitophilus oryzae *(Linnaeus, 1763) Coleoptera: Curculionidae)*

*Distribution:* The rice weevil is highly favored by the hot and humid climate. Being cosmopolitan in nature causes huge economic losses, both larva and adult cause severe damage.

*Host range:* Crops like paddy, wheat, millet, barley, maize, sorghum dried beans, cotton, nuts, cereals, wheat, corn, flour, pasta, dried flowers, decorative ornaments, stored clothes, dried plants, bread, and other cereals are highly infested by this pest. This pest results in both qualitative and quantitative loss of these crops during their storage.

*Bionomics:* Rice weevil or Black weevils are small snout beetles, dark brown having 4 distinct patches on the elytra, and prominent spots on the thorax and abdomen. Adults are similar to granary weevils but differ in color, markings, presence of wings beneath wing covers, and thorax with densely pitted with round

**Figure 1.** *Dorsal view of adult of* Sitophilus granarius.

**Figure 2.** *Damage status of* Sitophilus granarius *on wheat.*

punctures (**Figure 3**). Adults are tiny about 2.5 mm long and dark brown in color. Mostly both sexes are alike but in male's rostrum is short and broader. Females lay about 300–400 eggs. Adults are strong fliers and fly from granaries to granaries and to the grain fields for direct infestation. During summer life cycle is very short as compared to winter. Under hot and humid weather eggs take 4–5 days to hatch but under cold conditions eggs take 6–9 days to hatch. The newly hatched larvae bore into the kernel of the grain. Grubs are white in color, curved with a yellow or brown head's and hitting jaws. As grubs emerge from eggs they start feeding on the starchy material of the seeds, till it becomes fully grown and leaves behind only intact pericarp shell which is filled with grass. The grub stage mainly lasts for 19–34 days and then pupates to a non-feeding pupal stage after passing away prepupa for 2–3 days. The pupal stage mainly lasts for almost 1 week and after that adult emerges out of it and starts breeding. This pest completes its life cycle within a month. Most of the severely damaged crops resemble moldy grains.

*Damage symptoms:* Both larva and adult of this pest are extremely damaging larva enters inside the grain and then starts living and feeding inside the grain due to which irregular holes of about 1.5 mm diameter are produced on the grain. These pests cause extreme damage to stored grains.

*4.1.3 Broad-nosed grain weevil (*Caulophilus oryzae *(Gyllenhal, 1838) Coleoptera: Curculionidae)*

*Distribution:* Being cosmopolitan in nature, it is found all around the world.

**Figure 3.** *Dorsal view of adult of* Sitophilus oryzae*.*

*Host range:* Corn is the main host of this pest. Both fields as well as stored ones are very much susceptible to infestation.

*Bionomics:* Broad-nosed grain weevil is a small, dark brown with short and broad snout, and similar with granary beetle. It damages soft or damaged seeds and not the dry, hard, and uninjured seeds. These are also strong fliers and can damage the crop fields especially cornfields before the harvesting season. Gravid females lay around 200–300 small whitish eggs inside broken and soft grains. These eggs are hatched in a few days into small, white footless grubs and later into whitish pupae. During summer seasons when environmental conditions are favorable, a very small life cycle can be seen than during harsh cold winter seasons.

*Damage symptoms:* It damages soft or damaged seeds and not the dry, hard, and uninjured seeds.
