THE AGRICULTUEAL NEWS. 



Febkuary 



1904. 



INSECT NOTES. 



Fumigation of Imported Plants. 



The necessity for the adoption of a careful and systematic 

 scheme to prevent the introduction of insect pests into agri- 

 cultural centres lias been f(ircil)ly demonstrated in recent years, 

 and inspection and fumigation at ports of entry have been 

 shown to be more effective than any other method yet 

 devised. 



Of tlie insect pests tliat have become so serious as to 

 threaten even the e.xi.stence of several liorticultural or agri- 

 cultural enterprises, by far the greater numljer have been those 

 introduced from elsewhere, which have found more favour- 

 able conditions in the new localities than in the places from 

 which they came. Striking examples might be given of 

 such introductions, but a few of the more notable ones will 

 suffice. 



The grape Phylloxera {Phylloxera vastatrix) which, in 

 its native home in the United States was very insignificant 

 as a i^est, became, when introduced into the vine-growing 

 districts of Southern France, a most serious scoui-ge, causing 

 loss aggregating millions of dollars and threatening the 

 very existence of the vine industry. The Colorado 

 potato beetle {Dori/ji/iora decoidlne'itd), when first discovered, 

 was merely of scientific interest feeding upon wild plants, 

 but with the great increase in the area cultivated in the 

 Irish potato [Solanum tuheroswn) it has spread over the 

 entire North American continent and has become a i)est of 

 vital importance. The Cottony Cushion Scale (Iceri/a 

 pwclum) as a native was of minor imjiortance in Australia, 

 but when introduced into the citrus groves of California, 

 it nearly ruined the orange and lemon industries. The histories 

 of this pest in New Zealand and Cape of Good Hope, 

 of the Gypsy Moth (Portheiria dispar) in ^Massachusetts, 

 and the San -Jose Scale {Asju'diotuspenncioxiis) in the United 

 States all illustrate the serious danger that may arise from 

 imported pests. 



With a view to preventing anj- such serious trouble 

 many governments have ])assed laws to prohibit the importa- 

 tion of plants, cuttings, bulbs and other articles likely to be 

 infested with serious pests, or the treatment of such imported 

 articles at ports of entry in order to disinfect them. Among 

 the countries having such laws may be mentioned New- 

 Zealand, Cape of Good Hope, Germany, France, Switzerland, 

 Turkey and Canada. In the United States many .states have 

 laws requiring the regular insjiection, once a year, of orchards 

 and nurseries, and, if found free of noxious insect or other 

 pests, a certificate to that effect is given the proprietor. 

 Many states also in.sist that all nursery .stock shipped into 

 the .state shall be accomiianied with such a certificate of 

 inspection. 



In the West Indies also .something has been done along 

 this line. Jamaica has laws in operation recjuiring the 

 fumigation with hydrocyanic gas of all imported plants. 

 The fumigation as required by these laws has been carried 

 on for several years with marked success. The British Guiana 

 Court of Policy has recently |iassed a law entitled 'An 

 Ordinance to prevent the introduction into this Colony 



of Di.seases of Plants.' The planters in Domiiuca have asked 

 for similar enactment to protect the lime and orange industries 

 in that island, and already fumigating chandjers are in 

 course of construction and it will proliably not be long now 

 liefore suitablf laws are enacted to provide for the fumigation 

 of all iinjiortcd jilants. 



The general method ado}ited fur disinfecting nursery 

 stock and other jdants is known as the hydrocyanic gas 

 method, and when fumigation is mentioned in this connexion, 

 it always means that treatment, unless otherwise .specified. 



Hydrficyanic gas as an insecticide was first used in 

 combating the Cottony Cushion Scale in California, by 

 Mr. D. W. Coquillet in 1886. Since that time many 

 experiments have been tried with it and its great value as an 

 insecticide is now firmly establi.shed. It has been used for 

 fumigating nurseries, orchards, granaries, mills, houses, sliips, 

 etc., as well as jilant.s, fruits and vegetalilcs for import or 

 e.xport shipment. 



As ajiplied to the British West Indies fumigation of 

 imported plants cannot fail to be of tlie utmost benefit. It 

 is true that many insect pests and especially scale insects are 

 already to be found in the.se islands, Imt as pointed out liy 

 !Mr. !Maxwell-Lefroy in his paiier in the West Lndinn ISidlctin 

 (Vol. Ill, p. 240) entitled ' Scale Insects of the West Indies,' 

 about one-third of all the species of scale insects now known 

 in these islands are introduced si)ecies. Tlius, 80 species are 

 given as native, 4 as doubtful in origin, and .36 introduced. 

 Of the introduced sjiecies it is neces.sary to mention only two, 

 the Purple or ]Mussel Scale {Mi/tdusjiis citricola) and the 

 Orange Snow Scale {Chioimspis citri). These j)erhaps are the 

 most serious pests of orange and lime trees in these colonies. 

 On the other hand, the native West Indian lied Scale 

 (AsiiuIiotNs (iriiculatus), found ever3'where tliroughont the 

 AVest Indies and on a great variety of jilants, rarely becomes 

 a serious pest. These instances might be multiplied, luit 

 they should suffice to convince any who may have hitherto 

 doulited the value of preventive measures in dealing with 

 insect pests. The fact that we are already troubled with 

 pests of many kinds cannot for a moment be given as a 

 reason why we should allow others to be admitted, and 

 especially when it is remembered that imported or introduced 

 pests are likely, and almost certain, to become more 

 destructive than the native ones. Hence the necessity of 

 adopting an efficient means of preventing the introduction 

 of such pests will be api)arent. Tlie old saying ' an ounce 

 of prevention is worth a pound of cure ' may very truly 

 be applied to the matter of insect pests. That fumigation 

 with hydrocyanic gas furnishes the neces.sary iu'evention has 

 been amplj' proved by workers in economic entomology in 

 many countries and under varying circumstances. 



Carbon bisulphide for Parasol Ants. 



The Trinidad Bulletin of Miscellaneous Jnt'onnution 

 for January contains an interesting reference to the value of 

 carbon bisuli>liide as a destroyer of the parasol ant in 

 Trinidad. J\Ir. Hart states: 'it has been tried here in every 

 possible way on the " Bachrack " or parasol ant and has 

 been found very effective. It has also been recently used as 

 an insecticide for herbarium specimens and books and found 

 to be very eft'ecti^•e. ' 



A Cheap Paint. According to Ameriran Gardening 

 of January .30, ' a cheap and durable outdoor paint is made 

 by mixing hydraulic cement, to the consistency that can be 

 applied by a brush, with sweet skim milk. A quart of the- 

 cement requires about a gallon of milk.' 



