186 



THE AGRICULTURAL NEWS 



June 15, 1918. 



INSECT NOTES. 



SOME INSECT PESTS IN CUBA. 



In the last liumber of the .Igrkultiiral Ncivi (No. 420, 

 p. 174) an account ■v!\s, given of the Decree establishing the 

 Commission of Plant Sanitation in Cuba. This Commission 

 was established in 1916 to deal with the important j)i(jblenis 

 in the control of insect pests and plant diseases with which 

 Cuba is conlronted at the present time. 



It may tie of interest to give i-orae notes on the chief 

 insect pests with which the Commission has been concerned 

 since its establishment 



THE SPINY ciTKUS WHITE FLY (Akitrocanthus woginiai). 



In the Agricultural News iox January 13, 1917, there 

 was published an account of this insect, giving its early history, 

 its appearance and spread in a district in the eastern part of 

 Cuba, and the measures taken to control it there U|) to the 

 end of October 1916. The following notes on the subse- 

 quent history of this pest in Cuba up to the end of 1917 are 

 taken from Bulletin No. i of the Commission of Plant 

 Sanitation in Cuba, and from an article by P. Cardin in the 

 Revista (if Agricultura, C/imenio y Trabajo, ilarch 1918. 

 Mr. Cardin is Chief of the Department of Entomology at the 

 Agricultural Experiment Station, and a member of the said 

 Commission. 



The spiny white tiy was first discovered in Cuba in 

 August 191.") in a small area in the Guantanamo valley, and 

 further inspection .showed that there were a number of 

 smaller infestations in the district of Guantanamo, and the 

 city of Guantanamo was found to be thoroughly infested. 

 While species of citrus, mainly"oranges and lemons, are the 

 favourite food-plants of this pest, a number of other plants, 

 such as coffee, guava, mango, sapodilla, etc., are also 

 attacked. This white fly is a serious pest of citrus in the 

 neighbouring island of Jamaica, and it is now consid- 

 ered that it gained entrance to the Guantaiiiimo district 

 through the nearest port of Santiago de Cuba, between 

 which port and Jamaica there is frequent communi- 

 cation. From July 1916 to January 1917 the largest in 

 fe.sted area wa^ sprayed repeatedly, and the trees were restored 

 to good condition, although not entirely freed from the pest. 

 Owing to the internal troubles which occurred in Cuba 

 during the early months of 1917, the control work against 

 the spiny white fly had to be suspended, and no furthei report 

 is available. 



In November 1916 this insect was found in Havana, 

 and it .seems probable that the infestation originated with 

 the introduction of mango plants from Guantanamo 

 some two years previously. Further inspection determined 

 the fact that the spiny white tly was present in several 

 suburbs of Havana, and in some of the smaller towns to the 

 south of the city. Control measures were started immediate- 

 ly and have been carried on subseijuently. 



Mr. Cardin supplies some details of interest in 

 connexion with the life-cycle of Akurocaiilluis 'vnghiiiii. 

 The figgs are laid on the underside of the leaves, 

 and after hatching, the insect pa.s.ses through three 

 stages before becoming adult. As is the case with other 

 while Hies, it is during these intermediate stages between egg 

 and adult that the actual dimage is done. In a bad infes- 

 tation the underside of the leaves is almrist completely 

 covered with an incrustation of minute, shiny black, spiny, 

 scale-like insects, while the film of 'black blight', which often 

 accompanies outbreaks of scale insects, white (lies and rnealy- 

 bngs, further adds to the blackened appearance of the leaves. 



.\ bad infestation causes the leaves to curl up, turn yellow, 

 and eventually fall. The adults have dark bluish grey wings, 

 and bright reddish orange bodies. 



The complete life-cycle, according to Cardin, occupies 

 ibout si.xty-five days, so that there may be five generations 

 a year. The adult females are estimated to lay about forty 

 eygs on an average. This pest is therefore capable of a 

 rapid increase in a comparatively short time. 



.VmoiiH the enemies of the spiny white tly in Cuba are 

 ants; a small sjiider, in the webs of which large numbers of the 

 adults are caught; and a ladybird beetle { Chiloainis lai/i). 

 A species of A.schersonia f'.ingiis also attacks this pest, and 

 e.xperiments are being made with this fungus. Heavy rains 

 are said to be detrimental to this whit« fly. 



The Commission of Plant Sanitation is making every 

 effort to control this increasingly .serious pest by prohibiting 

 the importation of any of the fond-plants from other infest, 

 ed countries, by restricting the transportation of plants 

 within the island of Cuba, and by establishing an inspection 

 service in this conne.xion. 



KROiJHOl'PEE {Mo//ecp/icra hicincta). 



This insect has been known in Cuba since 1910 as 

 occasionally attacking sugar cane and certain forage grasses. 

 It came into prominence towards the end of 1916, when it 

 was discovered to have destroyed large areas of grass pasture 

 in the main cattle-rai,sing district of the island. This pastur- 

 age consists mainly of the so-called 'Parana' or 'Panama' 

 gra.ss {Paiiicum niimidianum), among which Guinea grass 

 {I'aiiiiinn inaximum) is sometimes found. Among other 

 species of grass attacked by the fioghopper are Sorghum 

 kalepe/isc: and Andropogon mi/rica/us- The worst outbreaks 

 of this pest occurred in the midst of fertile pastures where 

 the grass was in a vigorous conditi:)ii, and the attacks of the 

 froghoppers resulted in the complete drying up of large areas, 

 the grass being either killed outright or so weakened that it 

 was overrun by weeds. The damage is done mainly by the 

 nymphs, or immature stages, which attack the base of the 

 plant and the roots near the collar, gradually sucking the 

 plant dry. The adults also do some damage in this way, hut 

 fortunately their period of existence is somewhat shorter. 



The following details of the life-histoiy of this pest 

 may be of interest. The eggs were found to be laid on the 

 soil close to the plant in protected places. In the wet season 

 the eggs hatch in from t\Velve to twenty day.s, but under dry 

 conditions the eggs may remain unhatched as long as four 

 months until rains come, when they are able to hatch. This 

 pest is found in greatest abnndame during the rainy months 

 from July to November. The nymphs moult four times 

 before reaching the adult stage, and in the younger stages 

 are covered with a white froth, hence the name 'spittle 

 insects'. The complete development occupies from thirty-two 

 to forty days, under favourable conditions. 



Various methods are »ugk:ested for the control of the 

 froghopper in pastures. In the case of bad infestations it is 

 recommended that the dried up areas be burnt over, the tire 

 being controlled by lire-guards. My this means it is hoped 

 to destroy the different stages from egg toadiilt, though it 

 .seems probable that a certain proportion of the adults will 

 escape. It is further suggested that the adults should 

 be collected by the u.se of trap-lights, but the value of the.se 

 as a means of control is i|uestionable. The use of a machine 

 sfpinewhat resembling the 'hopi)erdo7,er' is also suggested for 

 collecting the adult froghoppers. This apparatus consists of 

 an upright, oblong framework covered with cloth which is 

 smeared with tar or tanglefoot. This machine is dragged 

 across the fields on runners, and catches a number of the 



