Plant Pathology - Study Mode
[#676] Downy mildew of pea caused by
Correct Answer
(A) Perenospora pisi
Explanation
Solution: Downy mildew of pea caused by Perenospora pisi. Downy mildew of peas is caused by the obligate parasite Peronospora pisi, which occurs sporadically throughout temperate pea-growing regions across the world. To screen pea lines against this biotrophic pathogen, a suitable and reproducible in vitro method using living plant material is required.
[#677] Urea of foliar spray should not contain biuret more than
Correct Answer
(B) 1.5%
Explanation
Solution: The Urea of foliar spray should not contain a biuret of more than 1.5%. Fertilizer-grade urea contains the impurity biuret which is toxic to the plant, especially when applied as a leaf dressing. Biuret of more than 1.5% can damage the root of the plant and also useful bacteria and chock the capillary of the root cell, Nitrogen carrying capacity will be reduced.
[#678] Both longitudinal and transverse septation are found in
Correct Answer
(C) Alternaria
Explanation
Solution: Both longitudinal and transverse septation are found in Alternaria. Alternaria is a genus of Deuteromycetes fungi. All species are known as major plant pathogens. Spores of Alternaria can be formed singly, but most often in chains. They are typically club-shaped and are highly septate, having divisions in both vertical and horizontal directions. The spore surfaces are usually smooth but may have small rounded warts creating a slightly rough surface.
[#679] Accessory pigments transfer their energy to chlorophyll molecules through
Correct Answer
(B) Resonance
Explanation
Solution: Accessory pigments transfer their energy to chlorophyll molecules through Resonance. It then transfers captured light from one pigment to the next as resonance energy, passing energy from one pigment to the other until reaching the special chlorophyll molecules in the reaction center. Chlorophyll also transfers resonance energy in the antenna complex, ending in the reaction center where specific chlorophylls P680 and P700 are located.
[#680] Which is a contact fungicide?
Correct Answer
(C) Captan
Explanation
Solution: Captan is a contact fungicide. Captan is a dicarboximide that is 3a,4,7,7a-tetrahydrophthalimide in which the hydrogen attached to the nitrogen is replaced by a trichloromethyl group. Captan works by coming into contact with a fungus and interrupting a key process in its life cycle. It can be toxic to many different fungal diseases. Captan is non-systemic, which means it is not expected to move through plants.