74 



JOUKNAL OF THE EOYAL HORTICULTURAL SOCIETY. 



Massachusetts Gypsy Moth Commission have established arsenate of lead 

 as one of the most desirable of arsenical insecticides. 



It is less liable to injure the foliage than Paris Green ; its colour is such 

 that it shows plainly where it has been applied. It remains in suspension 

 in water so well that there is no difficulty in applying it at uniform 

 strength. 



Insecticides for use against insects having sucking mouth parts. — 

 Kerosene emulsion has for many years been used against insects having 

 sucking mouth parts, such as scale insects, aphis, &c. The fruit grower, 

 how^ever, looks upon the preparation and application of this substance as 

 a very disagreeable task. It is not surprising, therefore, that there has 

 appeared within recent years spraying apparatus designed to mix kerosene 

 and water mechanically when the spray is applied and thus dilute the 

 kerosene to any desired extent and at the same time apply it constantly 

 at a uniform strength. Various kinds of apparatus designed to do this 

 work have been put upon the market. In some cases there are conflicting 

 reports as to the safety and reliability of this method of using kerosene as 

 an insecticide, and the process is regarded by many conservative horticul- 

 turists as being still in the experimental stage. 



Since the San Jos^ Scale has invaded some of the important fruit 

 growing sections of the Eastern United States, horticulturists and 

 entomologists have studied every way that ingenuity could devise for 

 keeping such an insect under control. In California fumigation with 

 hydrocyanic acid gas, one of the most deadly gases known, has come into 

 extensive use against this insect on orchard trees, the trees being covered 

 with tents during the process of fumigation. A wash known as the salt, 

 sulphur, and lime wash is also used on dormant trees. In the Eastern 

 United States the former has not come into use, and the latter of these 

 remedies has not passed beyond the experimental stage in orchard work. 

 The fumigation treatment for orchard trees in this section has not always 

 been attended with satisfactory results ; however, some of the most recent 

 experiments are giving very encouraging results. In the climate of the 

 Eastern States the trees appear to be more liable to injury from such 

 treatment than they are in California. 



But the advent of the San Jose Scale into the Eastern United 

 States has had at least one beneficent result. In order to keep it 

 as much as possible under control many States have adopted some system 

 of orchard and nursery inspection for the purpose of preventing the 

 introduction of this insect into uninfested localities and to check its spread 

 in infested localities as much as possible. Some States even require the 

 fumigation of all nursery stock before it is delivered. The lines of treat- 

 ment which have been put into practice because of the San Jose Scale 

 have unquestionably tended not only to prevent the dissemination of this 

 insect on nursery stock, but at the same time and in like manner have 

 also prevented the spread of other insect pests of economic importance. 

 Fruit growers in many cases are taking up the position that it is safest to 

 have all stock fumigated before receiving it on their premises. Many 

 nurserymen, therefore, who live in States where fumigation of nursery 

 Btock is not compulsory find it to their advantage to fumigate all stock 

 which they deliver. Accordingly they have built fumigatoriums and 



