1. Early shoot borer
Chilo infuscatellus Snellen (Crambidae: Lepidoptera)
Distribution: It is found to attack sugarcane in Tamil Nadu, Andhra Pradesh, Punjab, U.P., Bihar, West Bengal, Madhya Pradesh, Rajasthan and Maharashtra.
Nature of damage: The borer enters into young shoots and tunnels downwards. The upper portion of the central leaf whorl is thus cut off and dries up causing dead hearts in shoots from about a month old to 2 – 3 months crop. If the attack is in early stages the mother shoot dies completely and late attack induces profuse tillering.
Life history: The eggs are white and flat, laid in batches on the under surface of the leaves by the side of the midrib in three or more rows, one overlapping the other. Eggs are laid on the leaf sheath also. A moth may lay more than 200 eggs at a time and in each cluster 8 – 60 eggs will be found. The oviposition is at peak during May in March – April planted crop. The eggs hatch in 3 – 4 days. The caterpillars cut a hole on the side near ground level and enter the shoot and feed downwards. The affected tiller will decay emitting a foul smell. The caterpillar is white with five violet stripes on the dorsal side of the body with a brownish head. The crochets in the proleg are crescentic or semi circular. Each caterpillar migrates and attacks a number of shoots. The larval stage lasts for about 35 days and pupates inside the stem. The pupa is light brown in colour and the pupal period lasts for 10 days. The adult moth is small, pale grayish brown, the forewings with darker markings especially along the outer edge and the hind wings whitish. Total life cycle occupies 44 – 49 days.
(i) Light earthing up of the tillers at the early stages of the crop (month old) during May and June reduces the incidence. A second earthing a month later reduces the borer attack considerably.
(ii) Mulching with cane trash at the early stages also has been reported to reduce the incidence and help in conserving moisture.
(iii) Cutting the affected tillers as close to the ground as possible and destroying them.
(iv) Soil application of granules of cartap hydrochloride at 1 kg a.i./ha at planting followed by another application on 45th day for late planted crop.
(v) Cartap hydrochloride 4G, sevidol 8G and chlorpyriphos 10G at 1 kg a.i./ha as whorl application at 35th and 65th day are also found effective.
(vi) Inundative releases of the egg parasitoid Trichogramma chilonis @ 50,000/ha from first month of planting at 7 – 10 days interval till one month prior to harvest.
(vii) At 30th, 45th and 60th day of crop growth spray granulosis virus of Chilo infuscatellus (10-7 – 10-8 inclusion bodies/ml) at 500 l/ha.
(viii) Release of 125 gravid females of Sturmiopsis inferens (Tachinidae) per ha at 45th day of crop growth.
2. Internode borer
Chilo sacchariphagus indicus (Kapur) (Crambidae: Lepidoptera)
Distribution: The insect is found throughout India and usually occurs on sugarcane late in its growing phase during June – December. It is serious in Andhra Pradesh, Karnataka, Kerala, Tamil Nadu and Uttar Pradesh. The larva has been found feeding on Pearlmillet, sorghum, maize, paddy and wild plants like Sorghum spontaneum, S. fusca and Pennisetum hoockenhackeri.
Nature of damage: It infests the crop after the third month when internodes begin to form and continues till the time of harvest. Symptoms will be visible only on close examination. The affected node will be thinner than the other nodes. Mostly the attack is found on the first five internodes. It feeds on the internal tissue making it turn red. The bore hole is plugged with excreta. Due to the attack the quality of juice is reduced and in severe cases cane formation is affected resulting in loss of weight.
Life history: Oval flattish eggs are laid in rows on the leaf. Generally, two rows, one just overlapping the other are laid. Each row will contain 9 – 11 scale like eggs. Egg period lasts about 3 days. The larva bores near nodes and feeds on the fibrous tissue by tunneling. It migrates and damages many nodes. The larva is white with dark spots on the body and four violet stripes on the dorsal surface. The dorsal median line is absent. The head is shiny yellowish brown. The crochets on the prolegs are circular. Larval period lasts about 30 days. Pupates in the leaf sheath and the pupal period lasts about a week. The adult is a pale brown moth with a white hind wing. Total life cycle lasts about 40 – 45 days.
(i) Inundative release of the egg parasitoid Trichogramma chilonis @ 50,000 parasitoid/ha/week from the 4th up to 11th month after planting affords protection.
(ii) Use of resistant varieties are CO 285, 453, 513, 617, 853, 915, 1007, 1287, 6806 and COJ 46.
3. Top borer
Scirpophaga excerptalis Walk. (Pyraustinae: Lepidoptera)
Distribution: The insect has a wide distribution in India but is more serious in North India. It occurs on sugarcane in the later stages of growth during June – December and may persist till harvest. Wild Saccharum sp. is also attacked by this pest.
Nature of damage: Tunneling of midrib in a leaf, small holes in a parallel line in the freshly appeared leaves, dead heart which is reddish brown in the young crop (2 – 4 months old) and a bunchy top in a grown up crop are the characteristic symptoms. Sprouting of the eye buds affects the quality of the juice. Since the growth is restricted, the yield is also affected. It accounts for 20 – 30 % reduction in yield resulting in low juice quality and early maturity of the crop. The sucrose per cent in juice decreases by 2 units.
Life history: There are 5 broods reported in a year. The moth lays oval shaped flattish eggs in groups of 35 – 40, generally on the lower surface of the leaf and covers with crimson coloured hairs. The new larva hatches in 6 – 11 days and it bores through the mid rib and slowly reaches the central region. It feeds through the leaf whorl, enters the growing shoot from the top and feeds downwards. The caterpillar is cream yellowish white, very slender and soft. After entering the shoot it does not move out. Larval period lasts from 25 – 41 days. Pupates inside the burrow and emerges after 12 – 21 days. The adult comes out through the hole made by the larva before pupation. Moth is uniformly creamy white in colour. The first pair of wings of certain moths bears a black spot on each wing. Females have a crimson hairy tuft at the anal end. The total life cycle lasts 45 – 75 days. Heavy rains are usually conducive for the multiplication of the pest
(i) The egg masses and also the infested portions of plants may be collected and destroyed during the brood emergence period.
(ii) Release of the ichneumonid parasitoid Gambroides javensis Rohw. has been found to be promising in Tamil Nadu.
(iii) Variety Co 419 is comparatively resistant to this borer. Other resistant varieties are CoS 767, CoJ 67 and Co 1158.
(iv) Soil application of carbofuran at 2 kg a.i. /ha or phorate at 1 kg a.i./ha for the third brood during first week of July is recommended.
4. Sugarcane Leaf hopper
Pyrilla perpusilla Walker (Lophopidae: Homoptera)
Distribution: It is major pest of sugarcane in Punjab, Uttar Pradesh, Bihar and Maharashtra. Generally, it is a minor pest but sometimes assume a major form in different parts of India.
Nature of damage: Both the adults and nymphs are very active, jumping from leaf to leaf on slight disturbance. They suck the cell sap from the leaves and secrete honey dew which attracts the black fungus. Due to this feeding the leaves turns yellow and finally look withered and burnt with black encrustation.
Life history: The female bug lays greenish yellow eggs in clusters, generally on the undersurface of leaves and between the detached leaf sheaths and the stem. The eggs are covered with white cottony, waxy filaments. 10 – 15 eggs are found in a cluster and they hatch in about a week. The nymphs have two characteristic anal processes and feed on plant sap. They develop into adults in 50 – 60 days. The insects are generally found from August – September. The intermittent periods of drought during July – September, heavy manuring and irrigation and luxuriant growth help in its profuse multiplication. It is also found that broad and soft-leaved varieties are more susceptible to this pest.
(i) Release of the lepidopteran ectoparasitoid Epiricania melanoleuca @ 4000 – 5000 cocoons or @ 4 – 6 lakh eggs/ha checks its multiplication.
(ii) In case of severe infestation without the occurrence of the ectoparasitoid, spraying of endosulfan 0.07 % is quite effective.
Aleurolobus barodensis Mask. and Neomaskellia bergii (Sign.) (Aleyrodidae: Homoptera)
Distribution: A. barodensis in recent years has assumed serious proportions on sugarcane in Bihar, Gujarat, Haryana, Karnataka, Maharashtra, Punjab, Tamil Nadu and Uttar Pradesh and in a mild form in Andhra Pradesh. It is serious on ratoon crops under water-logged as well as drought conditions.
Nature of damage: The sap drainage by nymphs result in the leaf gradually turning yellow and pinkish and ultimately the leaf dries up. The nymphs excrete large quantities of honey dew which accumulates on the affected leaves and the leaves appear black due to development of sooty mould interfering with photosynthesis. High infestation causes stunted crop growth and reduces juice quality. Severe whitefly infestation may result in reduction in cane yield up to 24 % and loss in sugar up to 2.9 units.
Life history: The pale yellow adult female of A. barodensis lays about 80 eggs in linear masses on first and second top tender leaves. The eggs are fixed firmly on the leaf tissue on both the surfaces. The incubation period varies from 9 – 13 days. The nymphs feed by sucking the sap. The oval nymphs are black with fringes of wax and waxy deposit on body and the three nymphal instars last for respectively 4 – 7, 3 – 7 and 3 – 8 days. The fourth instar (pupal stage) lasts for 9 – 14 days. The last nymphal instar is the pupal stage from which through a T-shaped opening the adult emerges. The life-cycle is completed in 32 – 44 days.
(i) Discourage ratooning in low lying areas and avoid water logging. Remove lower leaves containing pupae periodically.
(ii) Spray imidacloprid 0.01% or monocrotophos 0.05% or acetamiprid @ 0.01% after removing infested lower leaves. At least two or more sprays will be required at fortnightly intervals.
6. Sugarcane woolly aphid,
Ceratovacuna lanigera Zehntner (Pemphigidae: Homoptera)
Distribution: It was reported as a minor pest of sugarcane in Assam, Nagaland, Sikkim, Tripura, U.P. and Bengal in 1974. In July 2002 severe infestation of this pest in sugarcane crop was noticed in Maharashtra. Later this pest was found distributed in Karnataka, Andhra Pradesh, Tamil Nadu, Kerala, Uttraranchal and Bihar. It is also reported to attack bamboo, Miscanthus sinensis.
Nature of damage: Nymphs and adults are found on the lower surface of the sugarcane leaves and suck the cell sap and excrete ‘honey dew’ which is dropped on the upper surface of the lower leaves. Honey dew encourages the growth of the fungus Capnodium spp. which results in black coating called ‘sooty mould’ on the upper surface of leaves affecting photosynthesis. Due to sap sucking, yellowish white spots develop on the leaves leading to drying of leaf edges and complete drying of leaves. Severe infestation causes mottling of leaves, stunted growth, and loss in sugarcane yield and sugar recovery. Losses up to 26% in sugarcane yield and 24% in sugar content have been reported.
Life history: Newly emerged nymphs are yellowish or greenish yellow in colour devoid of woolly filaments. Nymphs are found congregated at both the sides of the mid rib on the lower surface of the leaves. There are four instars observed after which they become adults. White coloured woolly filaments are observed on the dorsal side of the 3rd and 4th instar nymphs and not on the 1st and 2nd instars. Adults are black in colour and they possess two pairs of transparent wings and a pair of cornicles. Winged and wingless females are found to reproduce parthenogenetically throughout the year. Each female produced a maximum of 217 nymphs in 20 days. Nymphs completed four instars to become adults in 6 – 22 days. Overlapping generations are observed in the field.
(i) Paired or wider row planting of sugarcane.
(ii) Release of the natural enemies Dipha aphidivora Meyr. or Micromus igorotus in shade net cages (5m x 5m) @ 50/cage and allow them to develop and disperse by removing the cages.
(iii) Release of D. aphidivora larvae @ 1000/ha and M. igorotus larvae @ 2500/ha.
(iv) Need based application of metasystox 0.0375% or endosulfan 0.05% or dimethoate 0.045% in case of severe infestation without the presence of natural enemies.