Question
Write the modes by which insects affect the crop yield.
✓
Answer
Some common insect pests of stored grain and their mode of infection are:
- Gram dhora or Pulse beetle (Callosobruchus maculatus) Its grubs, damage the stored gram.
- Rice weevil: (Sitophilus oryza) Both grub and beetle (adult) damage rice.
- Khapra or Wheat weevil: (Trogoderma granarium) Infests stored wheat.
- Grain and flour moth: (Sitotroga cerealella) Its caterpillars bore into grains of rice, wheat, barley, maize and jowa.
- Rust red flour beetle: (Tribolium castaneum) Both larvae and adult damage flour and flour products.
- Rice moth: (Corcyra cephalonica) Larvae damage rice and maize.
- Lesser grain borer: (Rhizopertha dominica) Both grub and adult (beetle) damage the grains, reducing them to perforated shells.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A student heats a beaker containing ice and water. He measures the temperature of the content of the beaker as a function of time. Which of the following would correctly represent the result? Justify your choice.
What do you understand by the terms “balanced forces” and “unbalanced forces”? Explain with examples.
Write an activity to show that water can be made to boil even at a temperate below its normal boiling point $(100^\circ C)$.
→Differentiate between sclerenchyma and parenchyma tissue. Draw well labelled diagram.
There are four substances W, X, Y and Z. The substance W is a dark violet solid having diatomic molecules. A solution of W in alcohol is used as a common antiseptic C. The substance X is a white solid which is usually recovered from sea water on a large scale. The substance Y is a white solid which is insoluble in water and used in the form of small balls for the safe storage of woollen clothes. The substance Z is a yet another white solid which is used in making commonly used dry cells.
- Name (i) W (ii) X (iii) Y and (iv) Z.
- Out of W, X, Y and Z, which substance/ substances can undergo sublimation?
- Which substances organic in nature?
- What is the name of substance C?
- Which substance belongs to the halogen family?
Describe the various steps involved in the separation of iodine, iron filings and salt from a mixture.
Describe structure and functions of Golgi apparatus.
Draw a neat and labelled diagram of the human ear. With the help of this diagram, explain the construction and working of the human ear.
Show by using the graphical method that:
$\text{s}=\text{ut}+\frac{1}{2}\text{at}^2$
where the symbols have their usual meanings.
→$\text{s}=\text{ut}+\frac{1}{2}\text{at}^2$
where the symbols have their usual meanings.
A ball of mass $200g$ falls from a height of $5$ metres. What is its kinetic energy when it just reaches the ground? $(g = 9.8\ m/s).$
→