356 THE MONTHLY BULLETIN. 



Lectures. 



As soon as I took office, in obedience to the law, I commenced to lec- 

 ture in the various towns and counties as time and opportunity per- 

 mitted. I have now addressed over fifty audiences in thirty different 

 counties. I am very glad to do this, as it enables me to acquaint myself 

 Avith the needs, resources, and possibilities of the several counties of the 

 State and to come into closer touch with the county horticultural com- 

 missioners and the many horticulturists of the State. 



The Commission of Use. 



I wish again to invite most heartily all of you to use the office of the 

 State Horticultural Commissioner. There is no place in the country 

 where you can get such prompt, accurate, and helpful information as 

 with us. We have now a large, accurately-named, systematic collection 

 of insects which enables quick identiiication and practical advice. We 

 are also now equipped to give practical aid regarding the many fungoid 

 troubles that will more and more strike at the best interests of the fruit 

 growers. 



You can help us greatly by collecting and sending to us fifty or more 

 specimens of any insect that attracts attention, either as a friend or 

 enemy. Such action on your part will not only greatly add to our 

 collection at Sacramento, but will make us able to build up for each 

 county horticultural commissioner a collection that will greatly aid him 

 in his service to the public. 



Chairman Cook. W. H. Volck will now address the convention on 

 "The Control of Red Spiders." 



THE CONTROL OF RED SPIDERS. 



By W. H. Volck, Watsonville, Cal. 



The various kinds of mites which attack cultivated plants are at times 

 responsible for considerable damage to crops. In California we have 

 three important species which are frequently troublesome, namely, the 

 citrus red spider {Tetranychus mytilaspidis) , the yellow mite {Tet- 

 ranychus himaculatus Harvey) and the almond red spider (a species 

 of Bryohia). These mites, while commonly thought of as insects, are 

 really more closely related to the spiders. The species just men- 

 tioned are all very minute, being scarcely visible without a lens; but 

 their ability to multiply at a very rapid rate makes them capable of 

 inflicting much damage. The citrus red spider may pass through six- 

 teen generations in a year, and each female can produce thirty to sixty 

 individuals. Often, the greater portion of these will be females. Thus, 

 in nine weeks, the offspring of one mite can be upward of 1,800 indi- 

 viduals. Reproduction is by means of eggs which hatch whether fer- 

 tilized or not, the only difference being that the unfertilized eggs 



