35S THE MONTHLY BULLETIN. 



those mites present at the time of spraying and left the eggs to hatch, 

 a condition which demanded spraying at intervals of three weeks until 

 natural conditions became unfavorable to the red spiders. 



Dusting with sulphur has also been resorted to, but gave poor results, 

 owing to the failure in distribution and adhesion. For these reasons 

 the sulphur was mechanically mixed with water, to which had been 

 added some flour paste, and the trees thoroughly sprayed in such a 

 manner as to wet both surfaces of the leaves. This mixture proved 

 entirely successful, completely controlling the citrus red spider at any 

 season of the year. However, in this, as well as in most other matters, 

 prevention is preferable to cure, and makes the proper timing of the 

 spraying important. In this connection, it has been demonstrated that 

 under southern California conditions, spraying in August will render 

 orange and lemon orchards immune for the year. 



In actual practice, the sulphur-flour paste formula has not been as 

 much used as its merits justify, but resort has been had to spraying 

 with sulphur solutions. While these solutions kill by contact, as has 

 been explained, they do not have sufficient lasting effect. Such sulphur 

 solution as lye-sulphur and ]ime-sulphur will prove injurious to foliage 

 if used at all strong. The high dilution necessary to prevent injury 

 will leave so little sulphur deposited after the water has evaporated 

 that the young mites may not be killed when they hatch a week or ten 

 days later. The practice of using lime-sulphur solution could be much 

 improved by adding a few pounds of sublimed sulphur to each tank, 

 provided, of course, that there is sufficient agitation to keep it uni- 

 formly mixed. Finally, the use of flour paste is doubly advisable, as 

 will appear later. 



In 1903, the writer was sent to Sutter County to investigate a very 

 refractory case of almond red spider infestation. The usual practice 

 of dusting Math sulphur had proved absolutely worthless, for reasons 

 which are not fully under.stood. This infestation yielded to the sulphur- 

 flour paste mixture, although some lye-sulphur solution was added to 

 give quicker results on the adult mites, which were present in enormous 

 numbers. As with the citrus red spider, proper timing of the appli- 

 cation is important. The spraying should be done before much injury 

 has developed. This will be shortly after blooming, when enough 

 foliage has grown to hold the spray well. 



Another method of treatment appears to give promise with the 

 almond mite. That is winter spraying with crude oil emulsion. Such 

 deciduous trees as are injured by this r^d spider are frequently in need 

 of some winter spraying to kill moss and scale. Also, there appears to 

 be great possibilities in the way of stimulation by the use of oily winter 

 sprays. So marked are the stimulating effects of crude oil emulsion 

 that I predict considerable use of it, or some similar material, for that 

 purpose alone. It happens that the crude oil spray is also capable of 

 killing red spider eggs, and a marked degree of control has already been 

 observed as a result of such spraying. 



