DISEASES OF MINOR FRUIT PLANTS 355 



losses were stopped by restricting watering to one application in 

 the early morning, trashing the soil, and shading the plants 

 lightly with muslin. 



There is distinct varietal difference in susceptibiHty to 

 blossom-end rot. Brooks reports trials in which the percentage 

 of loss was zero with Bonny Best, low with Stone and Golden 

 Queen, medium with Earliana and Ponderosa, and heavy with 

 Matchless. 



Leaf-Mould. 



The leaf-mould disease of tomato foliage has been seen by the 

 writer on plants in St. Vincent, Barbados and Trinidad, grown 

 from American seed. It is reported by J. A. Stevenson to be 

 destructive to the first-crop (December-February) plantings in 

 Porto Rico, but absent from the second (April-June) crop. In 

 Trinidad its prevalence appears to be one of the main factors in 

 the failure of this crop during the wet season. 



Description. 



The disease is caused by the fungus Cladosporium fulvum Cke. 

 The conidiophores emerge on the underside of the leaves, forming 

 dense velvety patches of indefinite extent, white or grey at first, 

 later smoky brown. On the upper surface the leaves show yellow 

 patches which turn brown as the tissues die. The fungus also 

 appears in streaks aloiig the stem, and may form scattered patches 

 on the fruit. The conidia are elliptical, somewhat elongated, very 

 variable in size, mostly one- but sometimes two- or three- 

 septate, 



The disease spreads rapidly imder moist and shaded con- 

 ditions, and where these continue it can largely defoliate the 

 plants. It is inhibited by dry air and sun. 



Control. 



No varietal resistance to the disease appears to have been 

 recorded. Spraying with Bordeaux mixture has been recom- 

 mended as effective in the early stages of infection, but Stevenson 

 reports that repeated applications started before the fungus 

 appeared had no good effect in the experiments observed by him. 



Choice of season for planting and avoidance of humid situa- 

 tions are the measures indicated where this affection has proved 

 troublesome. 



Septoria Leaf-Spot. 



Leaf-spot is recognised as the most serious disease of tomatoes 

 occurring in the United States, where it has earned distinction 

 as the " tomato blight." It was first reported from the Argentine, 

 is widely distributed in Europe, and occurs in Austraha and 



