|
Class |
Insecta |
|
Order |
Orthoptera |
|
Family |
A.
psitaccina - Acrididae
P.
furcifera- Tettigoniidae |
Worldwide
in distribution.
Slant-faced grasshopper and katydid are voracious leaf eaters that make big
irregular holes before they consume the entire leaf.
Slant-faced
grasshopper
Eggs.
The
eggs are laid in the soil in groups. Embryonic
development begins soon after the egg is laid
Nymphs. The nymphs appear
similar to the adults except that they lack wings and have incomplete
reproductive organs.
There are five nymphal instars, and nymphs moult after each instar.
Adult.
The adult slant-faced grasshopper has a pointed conical head and measures
about 30-40 mm long. The upper part of the female body is greenish green
while that of the male is brownish. The hindwings are transparent with
pinkish base.
Katydid
Eggs.
The eggs are laid singly or in linear groups.
Nymphs.
There are 4 nymphal instars lasting from 30-41 days. They are grass green in
colour and measure about 17 mm (male) and 14 mm (female) long.
Adult.
The adult katydid is foliage green in colour with brownish red veins on
hindwings. They can be distinguished from grasshoppers by their long
antennae.
Taro
grasshopper
Eggs.
The eggs are laid in clusters which are protected with reddish brown gummy
substances.
Nymphs.
The nymphs are similar to the adults and are sometimes semi-aquatic.
Adults.
The adult is about 30 mm long and pale brown or green. It has black stripes
running from eyes to tips to tips of wings. Femur of hindlegs is
greenish yellow. Tibiae are bluish green with black-tipped spines.
Slant-faced
grasshopper
Eggs
are laid in the soil in groups, enclosed
in a sticky pod where loose soil get stuck. This pod protects the eggs
from parasites, desiccation and mechanical hazards. Embryonic development
begins soon after the egg is laid, and require warm conditions to develop. The
nymphs undergo five stages, moults at the completion of each stage, and become
capable of reproduction. They have under developed wings and are not capable of
flying. Warm
dry weather favours survival of the adults.
Katydid
Although
katydids are often referred to as grasshoppers, there are a
number of differences. Katydids have
long antennae and sword-like ovipositors while grasshoppers have short antennae
and blunt ovipositors. Another
difference is in their egg-laying behaviour. Katydids lay their eggs on plant
parts while grasshoppers lay theirs on the ground.
Taro
grasshopper
Using
its ovipositor, the female taro grasshopper bores into the petiole of the host
plant where it lays eggs in clusters that are protected with brown gummy
substances. Nymphs and adults of taro grasshopper are usually found on water
plants like taro and water hyacinths, the main hosts. Only the adults are
frequently seen feeding on sweetpotato.
Apart from sweetpotato they also feed on cabbage, cauliflower, citrus,
coconut, corn, cotton, cucumber, loofah, legumes, melon, mustard, radish, rice,
sorghum, sugarcane, tobacco, wheat and white potato
No control measure has been identified.
Amalin, D.M. and Vasquez, E.A. 1993. A handbook on Philippine sweetpotato
pests and their natural enemies. International Potato Center (CIP), Los Baņos,
Philippines. 82 p.
Davidowitz, G. 2002. Grasshoppers. http://www.desertmuseum.org/.
12 July 2002.
Evans, E. W. 1990. Grasshoppers in Utah: General Biology Fact Sheet No. 72,
Utah State University Extension. http://extension.usu.edu/files/factsheets/grassho3.pdf.
Roe, A. H. 2000. Grasshoppers and their control. Fact Sheet No. 48, Utah
State University Extension. http://extension.usu.edu/files/factsheets/grasshop.pdf.
Vasquez, E.A. and Sajise C. E. 1989. Pests of sweetpotato: Insects, mites and
diseases. PRIS and PRCRTC, Visayas State College of Agriculture, Baybay, Leyte,
Philippines. 66 pp.
Contributed
by: Erlinda Vasquez
and
Vilma Amante |
