- Pests:
- Termites (Odontotermes spp.)
- Armyworm (Mythimna separata)
- Aphids (Rhopalosiphum maidis)
- Diseases:
- Rust (Yellow Rust, Brown Rust, Black Rust)
- Loose Smut
- Karnal Bunt
- Powdery Mildew
Explain the construction of a spherical wavefront by using Huygens' principle.
The slope of the tangent to the curve \( x = \sin\theta \) and \( y = \cos 2\theta \) at \( \theta = \frac{\pi}{6} \) is ___________.