Plant Sanitation. 



514 



[December, 1911. 



oil 1 to 25 should be used. As these 

 are weak sprays, at least three to five 

 sprayings will have to be given at inter- 

 vals of two weeks in order to kill all 

 the insects. 



Windbreaks. 



Windbreaks (Pis. IV and V) are as 

 essential to a grove as a breakwater is 

 to an open harbour. In groves which are 

 thoroughly protected little, if any, 

 spraying is needed for the purple and 

 white scales, as the beneficial fungi, 

 which thrive under moist conditions, 

 hold the scale in check. 



The mango gives the best permanent 

 windbreak, and next to it comes the 

 bamboo, which grows somewhat faster, 

 but has no commercial value. 



Temporary windbreaks are numerous, 

 and among the best are those afforded 

 by the pigeon pea and the various 

 classes of bananas. Bananas produce a 

 a very thick break in one year, and in 

 this they excel the pigeon peas. Where 

 trees are planted very close together the 

 pigeon pea, which is a legume, should be 

 used as a break. 



Spray Pumps. 



The knapsack pump is the most con- 

 venient size for spraying very young 

 trees. The barrel pump is the most 

 popular among the planters of Porto 

 Rico. As the groves are developing 

 and more spraying becomes necessary, 

 it will soon be more practical to use 

 power sprayers. 



With these more spray can be applied 

 and at a less expense. At the present 

 time some of the planters cannot cover 

 their groves in less than three to four 

 weeks, and where sulphur sprays are 

 being used, with a repetition at intervals 

 of two weeks, it is almost impossible to 

 do thorough work, as the spraying 

 outfits are inadequate. 



THE MANGO WEEVIL. 

 (Cryptorhynchus mangiferce, Fab.) 



By C. L. Marlatt, 

 Entomologist and Acting Chief in 

 Absence of Chief. 



(Prom the United States Department of 

 Agriculture, Circular Nc, 141, 

 June 20, 1911.) 



The prospective mango industry of Florida is 

 jeopardized. The mango weevil is likely to be 

 introduced in the seeds of the mango. Ship- 

 ments of mango seeds now coming to this coun- 

 try are largely infested with this weevil. Intro- 

 ductions of any mango seed or ' fruit into mango- 

 growing districts are attended with the gravest 

 danger. The precautions indicated in this cir- 

 cular should be strictly carried out. 



The most serious insect pest of the 

 mango in oriental countries is the 

 mango weevil {Cryptorhynchus mangi- 

 ferce, Fab.) (fig. 1),* This weevil is related 

 to the boll weevil and the chestnut 

 weevil, and this, aside from its well- 

 known destructive work on the mangoes, 

 is sufficient indication of its undesir- 

 ability. It is probably of Indian or at 

 least of oriental origin, and has already 

 obtained foothold in most of the import- 

 ant mango-growing countries, being 

 carried readily with seed for planting. 

 It now inhabits all of the mango regions 

 bordering on the Indian Ocean and 

 adjacent islands, and occurs through- 

 out the East Indies, including the 

 Philippines and other groups of South 

 Pacific Islands. It has gained foothold 

 similarly in South Africa and Madagas- 

 car and numerous other points. Fortun- 

 ately this country is so far free from 

 this pest, and if it can be kept out the 

 mango industry which it is hoped to 

 develop in Florida and perhaps in the 

 other warmer parts of this country can 

 be given a very great advantage over 

 other mango-producing regions of the 

 world, The insect in its different stages 

 is illustrated, much enlarged, in figures 1 

 and 2,* from photographs by Mr. J. G- 

 Sanders, formerly of this bureau. 



As already indicated, this mango pest 

 belongs to the weevil family. The egg 

 is deposited in the fleshy part of the 

 fruit, and the young grub (fig. 2, a)* 

 burrows at once into the seed pod and 

 develops in the seed to a pupa (fig. 2, &)* 

 and finally to the adult, weevil, or beetle 

 (fig. 1).* The green mango soon heals up 

 over the egg slit, and there is very little, 

 if any, exterior indication of infestation. 

 The weevil or beetle is about one-fourth 

 of an inch long and dark brown in 

 colour. It remains in the seed for some 

 time, and may thus be easily distri- 

 buted with seed for planting or with 

 the ripened fruit. 



Protected as it is within the seed pod 

 and, in fact, within the seed itself 

 within the pod, it is not possible to 

 destroy it by fumigation with any 

 certainty. The only means of determin- 

 ing infestation is iu opening the seed 

 pod and removing the paper-like cover- 

 ing of the seed itself, when normally 

 the gnawing and excrement and dis- 

 colouration due to the work ot the 

 larvte and weevil can be noted. There- 

 fore all seeds introduced for planting in 

 this country in regions where mangoes 

 are grown should be opened in this 

 manner and all that indicate infestation 

 should be burned. As a matter of 



*Not reproduced. 



