Pest of Sugarcane (Pyrilla perpusilla) | Zoology Optional Notes for UPSC PDF Download

Distribution of Pyrilla perpusilla (Sugarcane plant hopper)

• Asian countries where Pyrilla perpusilla is found: Afghanistan, Bangladesh, Burma, Cambodia, India, Indonesia, Nepal, Pakistan, South China, Sri Lanka, Thailand, and Vietnam.
• Pyrilla perpusilla feeds and reproduces on a wide range of species from the Gramineae, Leguminae, and Moraceae families.

Identification of Pyrilla perpusilla

• The adult Pyrilla perpusilla is a pale tawny-yellow, soft-bodied insect with a prominently drawn forward head to form a snout.
• Male wingspan: 16 - 18 mm, Female wingspan: 19 - 21 mm.
  
• Female adults have cretaceous threads called anal pads arranged as bundles on the terminal segment.
• The fore wings are semi-opaque with a yellow-brown color and lightly covered with minute black spots.

Lifecycle of Pyrilla perpusilla

• Egg: Females lay eggs on the lower, shady, and concealed side of the leaves near the midrib. Eggs are oval-shaped, covered by pale waxy material, and turn brown before hatching. A female lays 600 - 800 eggs in her lifetime.
  
• Nymph: Passes through five nymphal instar stages to reach the adult stage. Each instar nymph has distinct features.
• First instar nymph: Whitish thorax with a thin transverse pale brown band on the posterior end. Last abdominal segment is green with whitish threads.
• Second instar nymph: Dark brown strips along the lateral margin.
• Third instar nymph: Thoracic region with one dark brown dorsal patch on either side. Abdominal segments are pale blue on the dorsal side and pale yellow on the ventral side.
• Fourth instar nymph: Abdominal segments have a dark brown band on the dorsal surface and pale green ventral surface.
• Fifth instar nymph: Abdominal segments have a dark brown transverse band on the dorsal surface and pale white ventral surface. Anal tufts are buff colored.
• Adult: Adults are initially white-colored but later turn straw-colored. Females measure 10 mm in length and 2.2 mm in breadth, while males measure 8 mm in length and 3.5 mm in breadth. Adult females are ready to mate 2 days after emerging from the 5th nymphal instar.

Damage caused by Pyrilla perpusilla

• Pyrilla perpusilla is a major pest in various Indian states and causes significant damage to sugarcane plants.
• Leaves turn yellowish white and wither away due to heavy infestation.
• Infected plants experience poor growth of seed sets and difficulties in milling cane.
• Sucking of sap from the leaves weakens the plant and reduces sucrose content by up to 50%.
• The hoppers exude a sweet sticky fluid called "honeydew" which promotes the growth of fungus Capnodium sps. The sooty mold affects photosynthesis when it covers the leaves completely.

Control measures of Pyrilla perpusilla

• Burning trash can help destroy unhatched eggs and overwintering nymphs.
• Dusting the fields with HCH 5-10% or methyl parathion (2%) during pre-monsoon can be helpful.
• Aerial sprayings of insecticides like Fenthion, Malathion, Phosphomidon, Monocrotophos, and Endosulphan are recommended during Pyrilla epidemics.