Erionota torus: Range extension and extent of crop damage in Western Ghats, India Essay

Erionota toroid ( Hesperiidae: Lepidoptera ) : Range extension and extent of harvest harm in Western Ghats, India


Erionota toroidEvans ( 1942 ) ; was described originally from Sikkim, India in the twelvemonth 1942. The species occurs from Sikkim boulder clay Taiwan and the Malay peninsula.E. Toruswasn’t reported in India since 1956. It was discovered in Ernakulam, Kerala in 2013. It is a known plague species which feeds on the commercially of importMusa paradisiaca.Field studies indicated that E.torus is distributed all across Kerala and is distributing due norths. About 3 % of entire works harm in 2013 in Kerala and 29 % of the entire works harm in Kodagu was infested by E. Torus. In this paper, we give a elaborate history of its scope extension, harm and the potency of its sister taxa to germinate into serious plagues.

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Insects are the most abundant group of beings in the universe with about 1 million species described as of now. They exhibit great diverseness in footings of morphology, home ground, reproduction and nutrition. (1) Plant-eating insects identify workss based on chemical signals from the workss. The workss in bend and hence can potentially go plagues when they feed on commercially of import workss. There are many insects which have become destructive worldwide and do significant harm to economic system and agribusiness. For case, the desert locust ( Schistocerca gregaria ) a good studied plague species which occurs from Northern Africa to Western India and causes one million millions of dollars worth of agricultural harm every twelvemonth. They feed on about all the aerial parts of the workss including root, Similarly, the Khapra beetle ; which originated from India is one of the world’s deadliest plague which feeds on dried harvests.

Lepidoptera is one of the most of import orders of insects which are known to do significant agricultural harm. The larvae of Lepidoptera are plant-eating in nature and hence can go possible plagues. Helicoverpa armigera ( Noctuidae: Lepidoptera ) ,6 a widely distributed species, is a plague on many commercially of import harvests. Annual harm sums to more than $ 5 billion worldwide.

There are several lepidopteran plagues in India which are known to do significant harm to economically of import harvests. DBT ( Fam: ) which feeds on workss belonging to the household Brassicasese causes harm upto 16million $ per twelvemonth. Another plague DMT ( Fam: )

The genus Erionota is spread across South and South east Asia. The genus feeds chiefly on the members of Musaceae and Arecaceae. There are two species of Erionota which occurs in the Indian subcontinent i.e Erionota thrax and Erionota toroid. Both species are confined to the North eastern Region from Sikkim to Arunachal Pradesh. However, Erionota thrax has been reported in A & A ; N. In this paper, we report the infestation of banana by Erionota toroid in the western ghats, South India, along with its harm and possible control.

Materials and Methods:

Field studies were conducted from August 2013 to December 2013 in Kerala ( 8.5074° N, 76.9730° Tocopherol ) and in August 2014 and September 2014 in Karnataka ( 12.9702° N, 77.5603° Tocopherol ) . Field observations were carried out between 0800 hours to 1600 hours every twenty-four hours during the study period. Sampling was carried out both in cultivated plantations and in the natural state. After the constitution of infestation in the part, the following informations were recorded: the figure of workss infected per plantation, the life phase ofE. toroid, the entire figure of eggs/larvae/pupae overruning each works, the larval instars present on each works, history ofE. toroidharm and pesticide use. The degree of harm to infested workss was determined on a graduated table of 1-5 ; where 1 = minor harm to the works where the infestation was seen merely on few foliages without significant harm ; 2 = significant harm to few foliages with many or few larvae ; 3 = significant harm to the works where few foliages have been wholly eaten ; 4 = monolithic harm to the works where all the foliages have been eaten ; 5 = decease of the whole works due to E. torus infestation along with remotion of works by the husbandman.


Larval Host Plant Data:

The larval host works informations forErionotaand its sister taxa were chiefly obtained from Lepidoptera Host Plant database ( HOSTS ) which provides systematic information with literature mentions along with published literature and personal communications. ( kunte, winter blyth, Evanss, swinhoe )

Pest species:

Erionota toroidThe grownups are crepuscular in nature. The larvae of E.torus is known to feed on Musa paradisiaca and on members from Arecaceae.

Egg: The eggs are laid in batches runing from 4- 40 on either side of the foliage ( per. Obs. ) . The eggs are hemi spherical and white in coloring material when laid and bit by bit turns ruddy.

Larva: The larvae provender onMusa paradisiacaand on Palms. The freshly hatched larvae are green in colour with a black caput. They feed on the egg shell after hatching and organize foliage axial rotations in which they rest and feed. The early instars are xanthous in coloring material with a black caput. The in-between and late instars are white in coloring material with a black caput. They besides have a white pulverization on their organic structure and the measure of the pulverization increases with promotion to the following instar. The larvae range a length of about 50 millimeters ( per. Ob. ) The larvae roll the foliage and provender from inside the axial rotation. Pupation occurs inside the axial rotation.

Pupa: The pupae are formed inside the cell ( leaf axial rotation ) and are brown in colour. They vibrate smartly when handled.

The full life rhythm takes 30 – 35 yearss from the twenty-four hours of oviposition ( per. obs. ) . ( SOM Fig.1a-p ) .

More images of the species can be found at hypertext transfer protocol: //


Historical distribution and scope extension:

E. toroidwas described by Evans W H in the twelvemonth 1941 with Sikkim ( India ) as the type vicinity. Its distributional scope extends from Uttarakhand in India boulder clay Taiwan in the E along with the full Malay part. Its historical scope in India was confined to the Western Himalayas from Uttarakhand to Arunachal Pradesh in the E ( Fig.1a ) .E. toroidwas discovered in Ernakulam, Kerala in August 2013. This spying from Kerala is the first study of this species in Southern India. It is a scope extension from its antecedently known scope in North East India. Subsequent studies indicated the presence ofE. toroidacross Kerala in 2013 and its infestation was spread to Kodagu in Karnataka in 2014. ( Fig.1a )

Degree of Damage:

Our field studies in Kerala established the infestation ofE. toroidin 7 territories. This contributes to 50 % of the territories being infested with the hesperiid in 2013. Of these 7 territories, Ernakulam was the most affected followed by Palakkad ( Fig.1c ) . 991 banana workss were infested withE. toroidwhich accounted to 3 % of the entire works harm in Kerala. Most of the workss had minor harm due to infestation with a harm degree of 1. The harm extent was high in Ernakulam a s a important proportion of the workss were destroyed wholly ( Fig.1c ) .

E. toroidwas spotted in August 2014 at Kodagu in Karnataka. It was the lone infested territory in Karnataka from our trying. 1946 workss were infested and constituted a important 29.9 % of the entire harm. The harm extent was high with a harm degree of 4 and 5 across

Larval Host Plant dealingss in Erionota clade:

The phyletic relationships of the Erionota clade is represented in the Fig. 2A. All taxa in the clade feed chiefly on liliopsids belonging to the orders Poales, Arecales, Zingiberales and Asparagales. The households Arecaceae and Poaceae are the most used hosts by the clade. The genus Erionota feeds entirely on Musaceae and is known to on occasion feed on Arecaceae.


Our record of Erionota toroid is the first study of this species in recent times. Erionota toroid if frequently confused with E. thrax as both species are similar morphologically. Out record confirms the presence of Erionota toroid in the Western Ghats. Since bulk of the banana plantation is grown in South India, this species can present as a possible menace to the banana selling in the hereafter. The caterpillars feed entirely on the foliages. This in bend shackles the overall fruit production. The foliages are besides commercially of import and hence, the harm caused by Erionota toroid is economically important.

Our consequences show that the infestation of E. toroids increased from 3 % to 29 % over a period of one twelvemonth. This indicates that E. torus is distributing at a faster rate across South India. It is unsure to find the way and period of its infestation in South India.Even though E. toroid was discovered in August 2013 in Kerala and August 2014 in Karnataka, it is apparent from the scope of its infestation that E. toroidmight hold been present in South India before it was discovered in August 2013. Insects are known to go to new topographic points through the transit of nutrient stuffs and it is extremely possible that E. toroid caterpillars reached South India by similar methods.

The harm degree caused by E. toroid during our study in Kerala was minimum on bulk of the workss. This can be attributed to the fact that bulk of the workss had immature caterpillars and hence hadn’t caused much harm. The harm degree was nevertheless terrible in ernakulam due to the presence of late instar caterpillars in the plantations. This is due to the random trying done at different times. The degree of harm was terrible in Kodagu, Karnataka due to the same ground. Late instar caterpillars feed sociably and besides do larger foliage axial rotations, therefore bring downing more harm to the works. Eggs and early instars are hard to descry by husbandmans as they are little in size and the harm looks like a little cutwhich is mistaken for some other ground.Ignorance by the husbandmans helps in increasing their population and besides in distributing the pest species to newer countries.

Along with the larvae of E. toroid, several other moth larvae were seen feeding on the banana plantations in our survey ( SOM fig3 ) . We nevertheless couldn’t determine the individuality of those caterpillars and were excluded from our survey.

Development of host works usage by E toroid

The Erionota clade provenders on Areaceae, Poaceae and Zingiberaceae households which are economically of import.

Control of E toroid in South India:

The genus Erionota has x species which originated from South andSouth East Asia and has spread every bit far as Australia in the South and Hawaii in the West.Of the x species, E. thrax and E. toroids have known to do significant harm to Banana production.

Mau et Al ( 1980 ) have mentioned that the harm caused by E. thrax in Hawaii was 80 % and had affected the banana industry to a great extent. E. toroid besides seems to hold similar potency as both species portionindistinguishable belongingss.Control of E. toroid is non necessary in countries with less population. When the


1Grimaldi, David, and Michael S. Engel.Development of the Insects. Cambridge University Press, 2005.