Contents - LAC Biosafety

208 Insect pests in plantations: case studies
insects were able to survive for several months without any visible feeding
although some feeding signs were seen on the tender foliage of some plants.
Aggregations of the pentatomid bug were found again in March 1992, after a
build-up occurred in February 1992 on flowered bamboo some distance away.
The insects completely destroyed the bamboo seed crop. Occasional outbreaks
of U. montana, associated with bamboo flowering have also been reported from
several other places in India – in 1917 at Mysore, Karnataka State; on various
occasions in Madhya Pradesh, including one during 1982–83 at Chandrapur and
adjoining areas etc. (Beeson, 1941; Singh, 1990). Outbreaks have also occurred
in Myanmar. These outbreaks are spectacular because of the production of
millions of bugs which aggregate on all kinds of vegetation and persist for
several months. Apparently, the enormous population build-up during the
mass flowering of bamboo declines slowly when the food supply is depleted.
Some birds are also known to feed on the bugs.
In general, bamboo plantations in the tropics are practically free of pests,
although as noted above some defoliators, sap suckers and culm and shoot
borers are potentially capable of causing damage. It appears that normally the
pests are kept in check by natural enemies.
10.5 Casuarina species (Casuarinaceae)
Two species of Casuarina, i.e. C. equisetifolia and C. junghuhniana are
important plantation species in the tropics. They are relatively fast-growing,
nitrogen-fixing tree species. The leaves are minute and scale-like; the jointed
green branchlets (needles) perform the functions of leaves.
10.5.1 Casuarina equisetifolia
Tree profile
Casuarina equisetifolia L. occurs naturally on the tropical coastlines
of Australia, on several islands in the Pacific, and in several countries in
Southeast Asia, including Indonesia, Malaysia, Myanmar, the Philippines and
Thailand. It has been introduced to many countries elsewhere in Asia, west
and east Africa, central and south America and the Caribbean. Extensive
plantations have been established in China, Cuba, India, Kenya, Puerto Rico,
Thailand and Vietnam (CABI, 2005). The tree attains a height of over 30 m and is
dioecious. It is salt-tolerant and grows well on sandy coastlines. It is planted
widely for coastal erosion control and to act as a windbreak. The wood is hard
and strong and is used for poles, scaffolding and fuel. Planted also as an