234 



THE AGRICULTURAL NEWS. 



July 19, 1913. 



INSECT NOTES. 



THE CORN EAR WORM ON RICE. 

 In the Journal of the Board of Af/ricultme of British 

 Guiana for April 1913 (Vol VI, No. I) ihere is an inter- 

 esting article by G. E. Bodkin, B.A., Government Economic 

 Biologist, which, under the lieading The Jlice Caterpillar, 

 gives a very complete account of the life history of /.cry'//.V- 

 <j7)M frugiperda, and describes its attacks on rice in that 

 colony. 



rOPULAR SYNONYMY. 



This insect has frequently lieeii referred to in the Agri- 

 ridtural A'ews (See \'ol. IV, p.90; Vol. X, p.74; Vol. XI, p. 

 346) as a pest of Indian corn atiacking the leaves and ears, 

 and of cotton, attacking the bolls in the same way .^s the 

 Jjoll worm {llciuitlds obsohta). 



In the United States, Laphyyma fruyijierda is commonly 

 called the fall army worm. In the Lesser Antilles it is 

 known as the corn ear worm, and is often confused with the 

 cotton boll worm when it attacks cotton: and, now, because 

 of its occurrence as a pest of rice, it receives the common 

 name of rice caterpillar. 



This insect is of very wide distribution thro-ugh North, 

 South and Central America and the West Indies. In 

 addition to the food plants already mentioned (cor,n, cotton 

 pnd rice) sugar cane, grasses, clover and peas have been 

 attacked by it. 



METHODS 01' CONTROL. 



In connexion with the control of the rice caterpillar the 

 use of dry, powdered le.ad arsenate is recommended when 

 this method can be adopted Flooding the rice nursery beds 

 is also believed to be a valuable means of control. The 

 caterpillars come to the surface of tho water, where they 

 may be collected by hand, and then destroyed. 



Wild birds are useful aids to control, and Mr. Bodkin 

 suggests that perches should be erected to attract them to 

 the vicinity of the nursery beds. 



NATDRAL KNEMIES. 



Laphy'jma frugiperda is controlled to a certain extent 

 by several natural enemies. A few of these, which occur in 

 British Guiana.are a hymenopterous parasite, a lady-bird beetle, 

 and a wasp, Pollstes nigrireps: all of these attack the insect 

 in its larval stage No egg parasites have as yet been found 

 in ]5ritish (Juiana. The following account of a parasite of 

 Laphygnia frugiperdii in the United States is taken from 

 the same number of the Journal of tin lloird of Agriculture 

 of British Guiana that contains the account of the rice 

 caterpillar: — 



•Issue No. 6 of Vol. V of the Journal of Econovdc 

 Jintomologij, contains an exceedingly interesting account 

 of the parasitism of Laphi/gma frugiperda by Clielonus 

 texaniis, Cress. Apparently this insect has the peculiar habit 

 of ovipositing in the eggs of Laphygnia, while the adult 

 parasite emerges from the larva. The .adult parasite is 

 approximately half as large as an ordinary house fly, 

 and about as large as a ma^s of sixty I.ajihygraa eggs. 

 Eggs of Laphygnia thus parasitized hatch in a normal 

 manner, but the larva when about half grown prepares 

 a pupal cell supported by a finen^eshed silken cocoon. Two 

 days after the completion of this cell, the larva dies, and on 

 the following day the larva of the parasite emerges from 

 a hole in the centre of the body of the caterpillar. The 

 larva of the parasite then commences to spin its cocoon of 

 white silk within the yellow tocoon of its host, taking 

 several days for the process. A parallel case was observed 



by the writer [Mr. Bodkin] in the cane fields of Porto Rico 

 early in January of -this year. As Laphygma frugiperda 

 commonly occurs in British Guiana it is cjuite possible that 

 this curious parasite is also present.' 



THE CONTROL OF FROGHOPPERS. 



The Department of Agriculture, Trinidad (June 20) has 

 recently issued an interesting circular (Special Circular No 7) 

 entitled Froghopper Notes by J. C. Kershaw, who is the 

 Entomologist engaged in a study of these insect.s in that 

 island. 



From this circular it appears that the recently 

 discovered 'Vermillion' egg parasite has not been bred in 

 captivity during the dry season in sufficient numbers to give 

 any great amount of encouragement that it can be used 

 under control as a satisfactory means of checking the 

 froghopper during the coming season. 



In addition to the use of the green muscardine fungus 

 which has given good results in the past and is being used 

 on a large scale at the present time, it is suggested that 

 there are three other means of combating the froghopper 

 which promise some measure of success. These are outlined 

 htrewith, together with certain observations on them. 



NITROLI.M. 



It is suggested that nitrolim (calcium cyanamide) should 

 be used primarily as a manure, and secondarily against the 

 froghopper nymphs. Its eft'ectiveness in this latter connex- 

 ion has not yet been determined. Nitrolim is an artificial 

 manure of particular interest because it contains a fairly 

 large proportion of nitrogen (18 per cent.) obtained from the 

 atmosphere by an electrical process (see Agricultural Kews, 

 Vol. XI, p.279). Its manurial eflect is not equ^l to 

 that of nitrate of soda, and it is much slower in its action, 

 according to experiments in British Guiana by Professor 

 Harrison and others (see West Indian Jhilleliu, Vol. .\III, 

 p. 131), and in Antigua (see Sugarcane Experiments in the 

 Li'eward Islands, 1911-12, p. 8-5, and Botanic Station 

 Report, Antigua, lltll-12, p..SO) 



A disadvantage in connexion with the use of nitrolim is 

 to be found in the fact that in the Tropics it rapidly loses a. 

 very considerable proportion of its nitrogen in the form of 

 ammonia. Nitrolim kept for nine months in British Guiana 

 lost 60 per cent, of its nitrogen. 



KEtlOSENKLYSOL KMULSION. 



In the preparation of this emulsion 3 oz. lyscl and 9 oz. 

 kerosene are stirred into 4 gallons (Imperial) of soft water. 

 This gives a 2per cent, emulsion which, it is stated, will- 

 remain in its emulsified condition indefinitely, that is to say 

 the kerosene and lysol will not separate from the water. 



The emulsion kills the froghoppers on coming into con- 

 tact with them. It is applied from a bottle through the 

 cork of which a short length of glass tube, of J inch bore, is 

 passed, the emulsion being shaken from the bottle in a small 

 jet, not a spray, into the axils of the leaves where the adult 

 froghoppers are in the habit of hiding. Used in this manner, 

 this emulsion should be very effective, and at the strength 

 suggested it should not have any injurious effect on the plant. 



A certain amount of difficulty is found in getting the 

 emulsion properly applied. Boys are said to do the work 

 better than men but they require constant supervision. 

 The best time for the work to be done is as soon as the 

 adults are to be seen on the canes in any numbers, and rf 

 this occurs while the canes are still small, not more than 



