IMPORTANT INSECT PREDATORS OF INDIA BY KHAN A. RAHMAN, B.Sc. (ERIN.), PH.D. (CANTAB)., F.R.E.S. (Ent..3mologist, Punjab Agricultural College, Lyallpur) Received April 9, 1940 (Communicated by Dr. Hamid Khan Bhatti) CONTENTS i . Introduction 67 2. Insect Predators .. .. .. .. .. 68 3. Future Lines of Research .. .. .. .. 74 Introduction INSECT pests of our country constitute a very serious problem. According to Sir Walter Morley Fletcher (Afzal Husain, 1938), " at a very modest esti- mate, the losses caused to India by insects that attack crops, timber and animal products cannot be less than 200 crores of rupees and a loss of over a million and a half of human lives ". The injurious insects attack in amazingly large numbers: 85,400 adults of the notorious Aspongopus Janus F. were collected from an area of 8 46 marlas " (66' x 33') of " kaddus " (Lagenaria vulgaris Seringe) by 20 men in 10 minutes on the 2nd of September, 1939, at Lyallpur. To prevent the injurious insects from becoming unduly abundant and destructive Ento- mologists have developed four arms of defence, viz., mechanical, cultural, chemical and biological. The work on the first three arms of defence has been in progress now for a number of years, but the work on the biological control of insect pests is of recent growth particularly in India. The biological control is based on the assumption that a number of insect pests are destroyed by their insect enemies. Such insects are group- able into (1) parasites and (2) predators. Both these types of insects, rival- ling each other in importance, rank among the Zamindars best and true friends. Of the two, predators are more numerous and more widely distributed than the parasites, and they show a greater range of adaptability (Thompson, 1929). In India (as elsewhere) the insect predators have not been studied as fhoroughly as their utility and economic importance would warrant. Further, 67 B1 F 68 Khan A. Rahman the little information that exists about them is scattered in the literature on Indian Entomology. In this article it is proposed to bring all this informa- tion together and to add to it the knowledge gained about them in the Punjab' most of which has not yet seen the light of the day. It is hoped that this article will stimulate interest in the much neglected but very much useful insect predators of our country. Insect Predators I. COLEOPTERA 2 I. Coccinellida, .— (1) Coccinella undecimpunctata L. —This beetle has been recorded from Behar and the Punjab; in the Punjab it is widely distributed. During June its life-cycle is completed in 6-11 days as follows: egg stage, 1-2; larval stage, 4-6; pupal stage, 1-3. A female lays about 90 eggs in her life-time. These eggs are laid in clusters by instalments. The newly emerged adults can stand starvation for 24 hours. C. undecimpunctata L. has been recorded feeding on wheat aphis (Macro- siphum granarium Kirby), cotton aphis (Aphis gossypii Glover) and mustard aphis Rhopalosiphum pseudobrassic Davis (Siphocoryne indobrassicce Das). Each grub, depending upon its age, feeds on 30-80, and an adult on 30-105, aphides daily. (2) Coccinella septempunctata L.—This is a widely distributed beetle in India which is active in winter only: It spends the period from April to October hiding among dense grasses and other sheltered places. During the active period its life-cycle is completed in about 50 days. It feeds on wheat aphis, mustard aphis and cotton aphis as well as on the nymphs of the mango-hoppers (Idiocerus atkinsoni Leth. and I. clypealis Leth.). (3) Coccinella repanda ab. transversalis F.—This beetle is fairly widely distributed in the Punjab and South India. It is active during winter when it feeds on AleyrodidT and Aphididx, 1 K. B. M. Afzal Husain, Entomologist to Government, Punjab (at present Vice-Chancellor of the University of the Punjab, Lahore), initiated research on insect predators in the Punjab as far back as 1920. This work was continued under his supervision and guidance upto 1938. Dur- ing this period much useful information was collected most of which lies buried in the Office files of the Entomologist to Government, Punjab, Lyallpur. I have made free use of this information in writing this article. 2 I am grateful to the Forest Entomologist, Dehra Dun, for his kindly checking the spellings of the names of Coleoptera and to the Imperial Entomologist, New Delhi, for his kindly checking the rest of the names of insects mentioned in the article. Important Insect Predators of India 69 (4) Coccinella 7-punctata ab. divaricataa?.—This beetle has been recorded feeding on the nymphs of Idiocerus spp. from Hoshiarpur (Punjab) and Pusa (Behar). (5) Chilomenes sexmaculata F.—This is the commonest of the Lady- bird beetles which is widely distributed in India. It is usually found in company with Coccinella septempunctata L. and C. repanda ab. transver- salis F. Each female can lay 100 eggs. In South India its life-history is com- pleted in 15-19 days as follows; egg stage, 2-3; larval stage, 10-12; pupal stage 3-4. It feeds on Aleyrodida', Aphidida3 and Coccida; injurious to crops and fruit trees. Its larvae and adults are said to be cannibalistic, for when food is scarce, they feed on their own eggs and larva . (6) Chilomenes bijugus infernalis Muls.—This is a wedge-shaped, metallic- black small beetle which has been found feeding on Woolly aphis (Eriosoma lanigerun Hans.) and occasionally on San Jose scale. [Quadraspidiotus (Aspidiotus) perniciosus Comst.] in the Kulu valley (Punjab). It is usually very abundant during May-July when it destroys Woolly aphis in large numbers. It is parasitized by a Eulophid, Tetrastichus sp. which affects appreciable reduction in its numbers at a time of the year (August-November) when its presence is most needed to check multiplication of and damage by, Woolly aphis. (7) Brumus suturalis F. —This is a very widely distributed Lady-bird beetle in India which is active throughout the year. It feeds on (1) eggs of sugarcane Top borer (Scirpophaga nivella F.: Pyralidar) and sugarcane leaf-hopper (Pyrilla perpusilla Walk.: Fulgoridae); (2) adults of the following Aleyrodide : Trialeurodes ricini Misra, Dialeurodes c.itri Ashm., Bemisia gossypiperda M. and L. and Aleurocanthus woglumi Ashby; (3) adults and nymphs of Aphis gossvpii Glover (= Aphis malvice Koch.) (AphididT); and (4) male puparia of Phenacoccus insolitus Green (Coccidw). (8) Scymnus coccivora Ramakrishna.—This is a tiny little beetle which feeds on the eggs of the " Nim " Mealy scale (Pulvinaria maxima Green). It is said to be very efficient in controlling the pest particularly during the hot summer months. (9) Scymnus gracilis Mots.—This beetle has so far been recorded from Lyallpur and Coimbatore only. At Lyallpur it remains active during March-November and hibernates as an adult during December-February. During the active period its life- 70 Khan A. Rahman cycle is completed in 7-49 days as follows: egg stage, 3-12; larval stage, 2-22; pupal stage, 2-15; it passes through 16 generations in this period. Each female can lay more than 170 eggs. S. gracilis Mots. is a specific predator of mites and in the Punjab it has been recorded feeding on the following species: Tetranvchus cucurbitce, T. fici Hirst, Partetranychus indicus Hirst and P. bioculatus. It prefers to feed on their eggs and resting stages. In the laboratory at 33° C. adults were found to feed on, on an average, 99 eggs and the larva; on 60-200 eggs (depending upon its age), daily. (10) Scymnus guimeti Muls.—This beetle has so far been reported from Delhi and Coimbatore only: at Delhi it has been recorded feeding on Cibius red scale (Aonidiella aurantii Mask.). (11) Scymnus xerampelinus Muls.—This beetle is common in the plains of India. Its pupal stage in the Punjab has been found to occupy about a week. It has been recorded feeding on Aphis gossypii Glover (= Aphis malva? Koch.) in the Punjab, and Phenacoccus insolitus Green in South India. Its larvw destroy 75 aphides a day. (12) Scymnus sp.—This beetle, which has been recorded from the Punjab only, remains active throughout the year. It feeds on the following Aley- rodidx: Trialeurodes ricini Misra, Dialeurodes decempunctata Quintance and Baker, D. citri Ashm., and Bemisia gossypiperda M. and L., and on the eggs of Pseudococcus sp. (Coccid e). (13) Sumnis renardi Ws.—The larva3 of this beetle have often been observed at Pusa feeding on Mango mealy bug (Monophlebus stebbingi ver. octocaudata Green). They feed on the yellow coloured body fluids of its victim which they obtain by gnawing through the skin. The pupal stage of this beetle occupies 8-9 days. (14) Jauravia binotata Gorh.—This beetle was found feeding in some numbers on Citrus red scale (Aonidiella orientalis Newst.) and Peach curl aphis (Brachvcaudus pruni Koch.) at Lyallpur in 1939. (15) Chilocorus nigritus F.—It is a widely distributed Lady-bird bettle in India. It has been reported feeding on Pulvinaria maxima Green in South India and aphides in the Punjab. (16) Ballia eucharis Muls.—This beetle is only recorded from the Kulu valley (Punjab) where it feeds on Woolly aphis (Eriosom2 lanigerum Haus.) as well as other aphides. Important Insect Predators of India 71 (17) Oenopia sauzeti Muls.—This beetle, like B. eucharis Muls., has so far been recorded only from the Kulu valley (Punjab) feeding on Woolly aphis and other aphids. (18) Ccelophora sp.—This beetle has been reported from Nilgiris feeding on the Green bug of coffee (Lecanium viride Green). (19) Adonia variagata s. sp. doubledavi Muls.—This beetle is recorded feeding on such aphids as Macrosiphum granarium Kirby, Rhopalosiphum pseudobrassica, Davis (= Siphocoryne indobrassicce Das), and Aphis gassypii Glover (= Aphis malva' Koch.) at Lvallpur.