Learn about the pests that damage sugarcane and its control.
1. Sugarcane Pyrilla, Pyrilla Perpusilla (Walker) (Hemiptera: Lophopidae):
Pyrilla or the sugarcane leafhopper is distributed throughout India and appears periodically as a destructive pest of sugarcane in Pakistan, Punjab, Haryana and Rajasthan. Apart from sugarcane, it feeds on wheat, barley (Hordeum vulgare Linn.), oats (Avena sativa Linn.), maize, sorghum, baru (Sorghum halepense), Guinea grass, swank (Echinolchloa spp.) and Sudan grass (Sorghum vulgare sudanese).
Both the nymphs and adults suck the cell sap usually from the underside of the leaves. When full-grown, a nymph is pale yellow, 10-15 mm long, and has two white prominent feathers like filaments at the tail end of its body. This leafhopper is very agile and jumps around in large numbers, making a faint noise when a person walks through a heavily infested field. The adult, equally active, is about 20 mm long and has a straw-coloured body with dark patches or spots on the wings. At the front end it has a snout like prolongation and prominent red eyes.
Life-Cycle:
The insect breeds throughout the year, migrating from one crop to another for fresh food. The adults lay 300-536 eggs in clusters on the underside of leaves during the summer and within the leafsheaths during winter. The clusters are covered with a white, fluffy material from the anal tufts of the females.
As this fluff is removed, oval, pale-white eggs are seen in 3-5 longitudinal rows of 35-50 each. The eggs hatch in 8-10 days in summer and in about 3-4 weeks during November or December. The nymphs which hatch out from the eggs are pale brown in colour and 1.3 mm long. At this stage they do not possess snout, wings and tufts.
Within a week they are characterised by the possession of two long tufts of waxy secretion at the end of the abdomen. They start sucking the sap of canes and grow to maturity through 5 stages within 8 weeks in summer and in 5-6 months in winter. The adults live for 27-52 days in the summer and 18-20 weeks in the winter. In all, 3-4 generations are completed in a year.
The common parasitoids of this pest are Ooencyrtus papilionis Ash mead (Encyrtidae), Tetrastichus pyrillae J.C. Crawford (Eulophidae), Lestodrynus pyrillae Kieffer, Drynius pyrillae Kieffer and Epiricania melanoleuca Fletcher (Epipyropidae). The eggs and nymphs are attacked by lady bird beetles namely Brumus suturalis (Fabricius), Menochilus sexmaculatus Fabricius and Coccinella septempunctata Linnaeus (Coccinellidae) as well as by chrysopods.
The conservation of egg parasitoids and introduction of E. melanoleuca in areas where it is absent is very useful and significant control of this pest can be achieved by the management of natural enemies. The white muscardine fungus, Metarhizium anisopliae (Metchnikoff) Sorokin, has also been reported from this pest.
Damage:
Succulent varieties of sugarcane with broad leaves are preferred by this pest but when it occurs in abundance, no variety is spared. Owing to the loss of cell-sap the leaves turn pale-yellow and shrivel up later. Even the canes dry up and die when the attack is very severe. The insects excrete a thick transparent liquid, known as honeydew which falls on the leaves and makes a good medium for the growth of a black mould.
Therefore, at times, the leaves acquire a sickly black appearance and the attacked crop can be spotted from a distance. The black coating interferes with photosynthesis and very little food is manufactured by the plants. The existing sucrose in the canes is also used up and about 35 per cent reduction in sugar yield is not uncommon. The cane juice becomes high in glucose, turns insipid and, if used for making gur, gives rise to a soggy mass which does not solidify properly.
Control:
(i) Pyrilla is parasitised by many natural parasites during, egg, nymph and adult stages. Every precaution should be observed for protecting the natural enemies.
(ii) Collect and destroy all the trashes immediately after harvest.
(iii) Remove sprouts and stubble from the sugarcane field.
(iv) Collect egg masses from the lower surface of the leaves and destroy them.
(v) Spray the crop with one litre of malathion 50EC per ha in 250 litres of water at an economic threshold level of 3-5 nymphs or adults per leaf.
2. Sugarcane Black Bug, Cavelerius Excavatus (Distant) (Hemiptera: Lygaeidae):
This pest is widely distributed throughout India and Pakistan, and it is believed that the ratooning practice has helped its multiplication in the Punjab. It has also been found feeding on rice, maize and a number of grasses.
Both the adults and nymphs cause damage by sucking cell sap from the plants. They are seen congregated under the leafsheaths or in the top whorl. The adults are 6-7 mm long, black with white patches on the wings extending slightly beyond the abdomen. The shape and colour of nymphs is similar to those of the adults but are smaller in size.
Life-Cycle:
The pest actively breeds throughout the year but during winter the adults and eggs are more noticeable. In summer, each bug lays 55-478 eggs in clusters of 14-67 on the inner side of the leafsheaths. The eggs are creamy white and hatch in 9-17 days. The nymphs grow through five stages and complete their development in 4-6 weeks. The adults are long-lived; males die earlier than the females.
The insects complete approximately three generations in a year. In winter, the eggs are laid in the soil at a depth of 5-7 cm and they hatch during the next spring. Thus, in March-April the new nymphs and the old adults die and only the nymphs remain and they mature by June. From then on, the generations overlap and all stages are found in the field.
Nardo cumaeus Nixon and N. phaeax Nixon parasitize the eggs of this bug.
Damage:
On young plants, the nymphs and adults suck cell-sap from the central whorl. On the grown up plants they prefer to feed within the leaf-sheaths, and varieties having broad and loosely attached sheaths are preferred by this pest. The attacked leaves become paler and also show holes after feeding.
Control:
Spray 875 ml chlorpyriphos 20EC in 1000 litres of water per ha. Direct the spray material into the leaf-whorl.
3. Sugarcane Whitefly, Aleurolobus Barodensis (Maskell) (Hemiptera: Aleyrodidae):
The white fly of sugarcane is found throughout the Indian Sub-continent and is a notorious pest in Gurdaspur, Jalandhar and Yamunanagar districts of Punjab and Haryana. In the absence of sugarcane, it can also survive on sarkanda (Saccharum munja). Damage is caused by the nymphs which suck the cell-sap from the leaves.
The grown up nymphs are about 3 mm long, oval in outline but flattened and scale like in form, thus remain sticking to the same spot on a leaf. They are black and have a silvery grey waxy coating on the body. The adults are small, delicate, pale-yellow insects about 3 mm long, and their wings have a white mealy appearance, mottled with black dots. They flutter about briskly, but they are not easily noticed in the field.
Life-Cycle:
The pest breeds practically throughout the year, except during winter when there are mostly nymphs and pupae present. Winged adults appear in the spring and soon after emergence, they copulate in an end to end position for 30-40 seconds. The female then lays 60-65 creamy white conical eggs which are glued to the surface of the leaves. The eggs are found in groups of 15-20, arranged in a single file.
Within a couple of hours, the eggs turn black and hatch in 8-10 days. On emergence, the young nymphs are pale yellow and they move away from the egg-shell to find a suitable place for feeding by the insertion of their piercing mouthparts. Their movements are very restricted and they complete their development in 25-30 days after passing through 4 instars.
The pupal stage lasts 10-11 days and the adults, on emergence, live only for 24-48 hours. Among adults, the females are in preponderance and they outnumber the males by 2: 1. The insect completes 9 generations in a year and in March-April; they migrate from the old to the new sugarcane plants. Their life is prolonged in autumn when the nymphal and pupal stages are completed in 3-4 months.
Several species of parasitoids have been collected from white flies and the commonly known from nymphs of this pest are Azotus delhiensis Lall, Encarsia issaci Mani, E. muliyali Mani and Eretmocerus delhiensis Mani (Aphelinidae).
Damage:
Only the nymphs cause damage by sucking the cell-sap. Yellow streaks appear on the attacked leaves and the crop acquires a palish green appearance. The general vitality of the plants is reduced, and the quality and quantity of gur production is poor because of subnormal crystalization of sugar. Sugar recovery is reduced by about 15-25 per cent.
A black mould develops on the honeydew excreted by the pest and it interferes with proper functioning of the leaves and renders them unfit as fodder. A comparatively poor crop with a thin stand is attacked more readily than a well-manured and heavy crop.
Control:
(i) Avoid ratooning especially in low lying and water logged areas.
(ii) Detrash lower leaves containing the puparia.
(iii) Spray 2.50-3.75 litres of malathion 50EC or 100 ml of imidacloprid 200SL or 1.5 litres of triazophos 40EC in 1000 litres of water per ha.
4. Sugarcane Spottedfly, Neomaskellia Bergii (Signoret) (Hemiptera: Aleyrodidae):
The sugarcane aleyrodid is found in India, Sri Lanka, Java, the Philippines, Reno Manila, Mauritius and Fiji. The pest is injurious in the nymphal stage only and apart from sugarcane it also attacks sorghum. The nymphs are pale brown to dark in colour and are covered with white-wax. The adult flies are pale brown with black markings on the fore wings. The hind wings are short, thin and more or less transparent.
Life-Cycle:
This pest is most active on sugarcane during September-October. The female lays 120-150 eggs in circular or semi-circular masses on the underside of the leaves during an oviposition period of 2-3 days. The freshly laid white egg is eliptical in shape and it turns black later on. The eggs hatch in 2-3 days. There are four moultings during larval period of 5-7 days. The pupal stage lasts 7-10 days and the life-cycle is completed in 15-18 days in September and 18-25 days from October onwards.
The puparia are attacked to the extent of 45 per cent by parasities, Eretmocerus delhiensis Mani, Encarsia neomaskelliae Prasad and E. isaaci Mani (Aphelinidae). The parasitized puparia turn dark in colour and can easily be distinguished from non-parasitized ones.
Damage:
The nymphs suck plant sap and in case of severe attack, cause stunting of canes and drying of leaves.
5. Sugarcane Scale Insect, Aulacaspis Tegalensis (Zehntner) (Hemiptera: Diaspididae):
The sugarcane scale is commonly found on this crop in Malaysia, Thailand, Indonesia, Taiwan, the Philippines and Mauritius. It is also reported to feed on sorghum in Tanzania and on the wild grass, Erianthus arundinaceus in Java. The adult female is sedentary having no legs or wings and lives inside a white covering or a white scale. It is about 1.8 mm long and 0.9 mm wide. The male is minute and is free living. It has a special sharp organ to penetrate the female’s scale covering.
Life-Cycle:
The fertilized female lays eggs inside her scale and these hatches into mobile nymphs which escape from under the cover. They wander over the host plant and eventually fix themselves and secrete a scale cover. They moult many times and develop differentially according to the sex; the females remaining sedentary. Dry conditions are believed to favour survival and dispersion of the ineffective “crawler” stage.
Damage:
The insects feed on stem parenchyma and by doing so prevent the accumulation of sucrose in the cane. Drying up of the canes may also result from heavy infestation. The infestation reduces germination by about 20 per cent, cane growth by 5.5 per cent, cane yield by 43 per cent, juice content by 0.30-41 per cent and jaggery production by 10 per cent.
Control:
(i) Give hot water treatment at planting time.
(ii) Dip setts for 15 minutes in 0.1 per cent malathion 50 EC before planting.
(iii) Spray 1.25 litres of malathion 50 EC or 2.0 litres of dimethoate 30 EC in 1250 litres of water per ha.
6. Sugarcane Mealybug, Saccharicoccus Sacchari (Cockered) (Hemiptera: Pseudococcidae):
This species and a number of others are minor pests of sugarcane. They also feed on reeds and some of the grasses. Mealybugs are seen clustered at the basal nodes of canes and are exposed when a leaf sheath is removed. Nymphs and the wingless female adults cause damage by sucking the cell-sap.
They are inert pink insects, having a rotund, sack-like, segmented body covered completely with a white mealy powder. The size, even among full-grown females, varies a great deal, but a large female measures about 5 mm in length and 2.5 mm in width. The males, whose only function is to fertilize the females, are sluggish having only one pair of wings and are short-lived.
Life-Cycle:
The pest breeds practically throughout the year. The females are highly fecund and lay a large number of eggs at short intervals. The eggs are yellowish, smooth, cylindrical and rounded at both ends and measure 0.35 mm in length and 0.16 mm in width. Within a few hours the eggs become soft and elongated, and the crawlers emerge.
The tiny young ones are transparent, pink and very active. They wander about for some time and spread all over the field or may even be blown away by the wind to the adjoining fields of sugarcane. Finding a suitable host plant, they force themselves underneath the leafsheaths near the basal nodes.
As the canes grow taller, the older bugs remain at the lower end and the crawlers reach the higher nodes. The nymphs feed voraciously and pass through 6 stages before they are full-grown in 2-3 weeks. The life of a full-grown winged female is approximately 3-5 days. The entire life-cycle is completed in about a month during the summer. The pest completes several generations in a year.
The coccinellids reported from this mealy bug are Pharoscymnus grimeti Mulsant, Scymnus coccivora Ramakrishna Ayyar, S. andrewsi Sie. and S. nubilis Mulsant A coccinellid, Hyperaspis trilineala Mulsant was introduced in Tamil Nadu and Karnataka in 1970.
Damage:
Mealy-bugs are first noticed in appreciable numbers when canes are four months old and from then on, they remain on the plants till harvest. Canes having tight fitting sheaths are more or less free from the attack, whereas a drought affected crop is more severely damaged. The bugs drain away large quantities of sap from the canes and befoul them by their mealy secretions and honeydew.
A sooty mould develops on these secretions giving a blackish appearance to the canes. It is also suspected that the mottling disease of sugarcane which is serious in certain parts of India is transmitted by these bugs. In severe cases of infestation, sucrose content decreases by 24 per cent and brix by 16 per cent.
Control:
Spray 1.25 litres of Malathion 50EC in 1250 litres of water per ha.
7. Sugarcane Woolly Aphid, Ceracovacuna Lanigera Zehntner (Hemiptera: Aphididae):
The sugarcane wooly aphid was first reported on sugarcane in 1897 from Java, Indonesia and later on reported as a serious pest of sugarcane in Asia. It is known to occur in India, Pakistan, Korea, Japan, China, Taiwan and the Philippines. In India, it was reported on sugarcane for the first time in West Bengal in 1958 and later it was reported from Assam, Sikkim, Tripura and Uttar Pradesh. The pest appeared in serious proportions in Maharashtra in 2002 and has spread to other states including Karnataka, Andhra Pradesh, Tamil Nadu, Kerala, Bihar and Uttarakhand.
Apterae are small to medium-sized, pale green to brown, covered with white woolly wax, forming dense colonies on the under surface of leaves, often attended by ants. Nymphs have little wax coating on body. Wax filaments increase gradually with age, third instar with clear intersegmental lines and siphunculi, full- grown aphid completely covered with white wooly covering. Alatae have brown-black head and thorax, and dusky transverse bands on abdominal dorsum. Soldier aphids are often seen in the colony.
Life-Cycle:
The aphid undergoes an anholocyclic life-cycle and no sexuals have been noticed in nature in Taiwan, The nymphal stage occupied 10 days and the alate about 14 days in Taiwan. The optimum temperature for aphid development ranged from 20 to 23°C and the aphids became inactive at temperatures below 15°C and above 28°C.
The nymphal development period varies under different temperature and photoperiod regimes. In Japan, apterous nymphal stages occupied 22-32 days. The average longevity of apterous and alate adults was 36 and 8.3 days, respectively. Average fecundity of apterous adult was 60 aphid nymphs, while it was 10 aphid nymphs in alate.
In Maharashtra, aphid population peaks from early August to September and again from November to February. The season from March to July appears to be the lean period. In Uttar Pradesh, the pest occurred during October to March and the population was low in June.
Several species of ladybird beetles like Synochyta grandis (Thunberg), Pseudoscymnus kurohime (Miyatake), Aniscilemnia dilatata (Fabricius). [Megalocaria dilatata (Fabricius)], Coelophora biplagiata (Swartz) and C. saucia Mulsant are quite effective predators of sugarcane woolly aphid. In addition, Chrysoperla carnea (Stephens), Dipha aphidivora Meyrick and Micromus igorotus (Banks) are potential predators of this pest and are promising candidates for augmentation. Two major parasitoids, namely Encarsia flavoscutellum Zehntner and Diaerelus oregmae Gahan, have been recorded from Indonesia (Java) and the Philippines, respectively, the former also occurring in India.
The common entomofungal pathogens, Beauveria bassina, Metarhizium anisophiae and Verticillium lecanii have been found to have only limited to moderate efficacy against the aphid.
Damage:
Initial infestation is seen on the under surface of the leaves along the midrib and then over the entire under surface, covering it with flocculent, waxy secretion. Copius honeydew secretion often covers the entire upper surface of the leaves, leading to growth of sooty mould.
Due to continuous sap sucking, the crop becomes stunted and continuous infestation leads to reduction in the length, circumference, weight and sugar content of the stalk, loss in tonnage and sugar recovery. The aphid infestation adversely affects the yield and cane quality.
Control:
(i) Maintain proper sanitation and avoid transport of infested leaves from one area to another.
(ii) Stripping of infested leaves and burning those help to avoid further spread of the pest,
(iii) Biological control by augmentation of the coccinellid predators, S. grandis and A. dilatata, has given good results.
(iv) Sprays of camphor oil (1%), yam and bean oil, tea seed oil, tea decoction emulsified with sodium oleate and leaf extract of tobacco have provided good control of the pest, and
(v) Spray 100 ml of imidacloprid 200SL or 1.25 litres of malathion 50EC or 2.0 litres of dimethoate 30EC in 1250 litres of water per ha.