652 INSECTS AFFECTING VEGETATION 



tional lines. The fact is apparent, however, that the present seedling 

 walnut groves have had their day and that they will gradually dis- 

 appear just as the seedling apple, the seedling orange and all other 

 fruits of the same nature are gradually supplanted by more desir- 

 able, definite varieties. The real hope of the walnut industry lies 

 in the future, and is based upon an entirely new start along the lines 

 just mentioned. Upon this basis there is absolutely no doubt but 

 that the walnut will again come into its own and prove one of our 

 most attractive and profitable crops. A complete bulletin upon wal- 

 nut culture in all of its phases is now under preparation by the senior 

 writer. (Cal. E. S. B. 218.) 



DISEASES OF STORED PRODUCTS. 



Rot Disease Losses in Storage. No sharp line can be drawn 

 between diseases of edible plant products which usually infect these 

 crops previous to harvest, and the rots, molds or decays in such fruits 

 and vegetables during storage. It has seemed best, for this reason, 

 to insert here a brief discussion of these storage troubles which apply 

 to products grown in our region. We can scarcely be called on to 

 present the facts concerning the diseases of citrus fruits in storage 

 or in transit. 



All growers of fruits and vegetables in our state are liable, how- 

 ever, to have had losses from rots of fruits and vegetables during stor- 

 age upon the farm. In the more recent custom of concentrating 

 such storage products in cold storage plants, especially constructed 

 for that purpose, the problem has only been transferred or trans- 

 planted: the difficulties have not been entirely overcome. 



For the fruits known as perishable, namely, for peaches, plums, 

 cherries and grapes, the custom of brief storage has become well 

 established; the rots or other injuries, such as those that come from 

 crushing, are well known. The storage rots are not different from 

 those commonly found in the orchards indeed, they are usually the 

 common soft-rot of stone fruits, Monilia fructigena. Storage or tran- 

 sit losses from it are but an accentuation of orchard conditions. Also 

 with the stone fruits, as a result of bruising and shipment, we have 

 various of the common molds which develop on the bruised surfaces. 

 The more usual ones are the common bread mold, Mucor, the blue 

 mold, Penicillium, or the almost equally frequent form of green 

 mold, Aspergillus. None of these, however, is likely to penetrate 

 very deeply and be a serious enemy of these fruits. This arises, how- 

 ever, not so much out of the lack of ability to injure by these mold 

 attacks, as from the very brief period of time which these tender 

 skinned stone fruits are held before consumption. As has been 

 pointed out by Powell and Smith, the same common molds, includ- 

 ing especially Penicillium, possibly with the aid of others, are sources 

 of serious loss in the handling of citrus fruits oranges, lemons, etc., 

 during their prolonged periods of transit and storage. 



In the case of grapes the losses are almost altogether due to 

 breaking of the skin following which molds and bacteria are liaible 

 to appear under favorable conditions. 



