| Locusts (Orthoptera: Acrididae)
Locust is one of the most important pest insect groups that affect bamboo. Some 34 locust species have been reported that attack bamboos in Asian countries. They are classified into a number of genera, of which Ceracris and Hieroglyphus are the most common. Both adults and nymphs feed on bamboo leaves and outbreaks usually cause complete defoliation of bamboo stands. Heavy and repeated defoliation will result in the death of bamboo plants.  Yellow-spined bamboo locust - Ceracris kiangsu Tsai
DISTRIBUTION Throughout the bamboo-growing areas in China. HOSTS Various monopodial and sympodial bamboos, as well as some agricultural crops; but prefers Phyllostachys pubescens. BIOLOGY The adult locust is about 30-40 mm long, green in colour, with a yellowish stripe from the vertex to the protergum. There is one generation per year overwintering as eggs in the soil. Nymphs hatch in May-June and take 46-69 days to develop fully, passing through five instars, to become adults during June-October. They gather on small bamboo plants for feeding and move on to bigger plants at the second instar stage. Nymphs feed in groups on leaves, starting from the top crown and moving downwards. Adults keep feeding for about 40 days before laying eggs. Eggs are laid in capsules, each containing about 20 eggs, in the soil at 3-4 cm depth. Both nymphs and adults are attracted to uric odour. (Shen Jizeng 1965; Xu Tiansen 1984a; Wang Shufen et al. 1990). Female adults have a strong preference in the selection of egg-laying site; eggs are mostly found on hot and dry sites with deep and loosened soil. DAMAGE CAUSED One of the most destructive of all
pest insects on CONTROL Soil-turning or spraying white fungus can play an important role in suppressing the population. If the locust population level is high, chemical control may be needed. The best methods are dusting BHC or spraying pyrethroids to control the newly hatched nymphs feeding in groups on small bamboo plants and wild grass, or smoking after they move on to bigger plants (Xiao Gangrou 1954; Ding Daomo and Zhang Shimei 1956; Anonymous 1960). Trapping is also recommended for controlling the locust (Guo Peide 1989). Xiao Gangrou (1959) has reviewed the biology and control measures of the locust. Ceracris nigricornis Walker
DISTRIBUTION Commonly seen in bamboo-growing areas in central and southern China. |
|||||||||
|
|||||||||
Fig. 1: Yellow-spined bamboo locust - Ceracris kiangsu a: female adult; b: male adult; c: back view of adult; d: egg and egg capsule; e-k: 1st to 5th instar of nymph BIOLOGY There is one generation per year for both species. Eggs are laid in winter in egg-capsules in the soil. Nymphs and adults emerge from April to early August and from July to mid December, respectively. They rarely reach epidemic population level, and often occur together with C. kiangsu (Shen Jizeng 1964). |
|||||||||
|
|||||||||
Fig. 2: Adult of yellow-spined bamboo locust - Ceracris kiangsu Phlaeoba angustidorsis Bolivar
DISTRIBUTION Widespread in central and south-eastern China. HOSTS Attacks mainly Phyllostachys species. BIOLOGY The adult is 20-30 mm long and has the colour of dry-grass. The front of the adult noticeably extends forwards and the protergum is ridged. The wings are shorter than the abdomen in length. There is one generation per year, and eggs overwinter in capsules laid in the soil from August to May. Nymphs hatch in May and take 45-50 days to develop fully, passing through four instars for males and five instars for females. Adults emerge from July to October and their longevity ranges from 90 to 110 days (Xu Tiansen and Lu Ruoqing 1987a). Rice grasshopper - Hieroglyphus banian Fabricius
DISTRIBUTION Parts of India; a serious epidemic of this species was recorded in Punjab during 1933-35 (Beeson 1941). HOSTS Principally a pest of rice, maize and wild grass; frequently affects Dendrocalamus strictus. BIOLOGY Green or brownish in colour. The adult lays eggs in the soil in November which do not hatch till June/July, the following year (Beeson 1941; Browne 1968). CONTROL Control measures have been described by Main (1912), and Rao and Cherian (1940). Eggs are parasitized by Scelio hieroglyphii Timb. (Hymenoptera). Dusting hoppers and adults with 5% and 10% BHC dust, respectively, gives effective control (Singh and Bhandari 1988). Hieroglyphus tonkinensis Bolivar
DISTRIBUTION Southern China. HOSTS Reported as an important pest insect of various bamboos classified to the genera of Bambusa, Sinobambusa, Lingnania, Dendrocalamus and Phyllostachys. The insect also attacks sugar-cane, rice and some other agricultural crops when bamboo leaves are in short supply. |
|||||||||
|
