524 INSECTS AFFECTING VEGETATION 



regular or irregular in outline. The lesions may occur as a number 

 of small spots no larger than a pin-head, or may involve a large por- 

 tion of the fruit. Fruit from trees where a considerable amount of 

 dropping has occurred should not be shipped, but the trees should 

 be treated and the disease cured before the fruit is allowed to be 

 picked or to come to the packing house. Not only will the infected 

 fruit become worthless in transit, but the handling of such fruit is 

 likely to cause infection of the healthy fruit. Infection occurs 

 through the skin of the fruit, and is not transmitted through the 

 tissues of the tree to the fruit. 



The first sign of loss from anthracnose is the dropping of a con- 

 siderable amount of fruit. This is more particularly true with 

 grapefruit than with tangerine and round oranges. This disease, 

 caused by Colletotrichum gloeosporioides, does the greatest amount 

 of damage to grapefruit and round oranges, though it has been ob- 

 served on all edible varieties of citrus fruits, including the lime. On 

 the latter it appears in the form of scab. 



It rarely occurs on fruit before it has begun to color, though 

 in some few cases, especially with tangerines, a large percentage of 

 the fruit has been attacked even before coloring. In such cases 

 much fruit has become infected before severe dropping occurs. The 

 fruit on poorly nourished and slightly debilitated trees is more sub- 

 ject to attack than fruit in groves that are perfectly healthy and in 

 full leafage. Fruit on trees that are overloaded is likely to be 

 attacked. Trees more or less affected by withertip are likely to lose 

 considerable fruit from anthracnose. On the other hand, the 

 fungus is not likely to make its first appearance in a grove in the 

 form of anthracnose. Withertip fungus is present in practically 

 every grove in the State, to a greater or less extent. One should 

 therefore constantly expect anthracnose to appear whenever any con- 

 siderable amount of dead wood occurs in the trees, or whenever there 

 is any considerable loss of foliage. (Fla. E. S. B. 108.) 



It can be readily distinguished from the affection usually spoken 

 of as ammoniated fruits by the fact that the anthracnose marking is 

 always sunken and lacks luster. Spots and patches caused by am- 

 moniation are not sunken, but are more likely to be slightly raised, 

 and their surface looks as if varnished or oiled. Anthracnose may 

 be distinguished from chemical injury by the fact that chemical in- 

 jury, w r hen occurring as the result of spraying, always occurs on the 

 part of the fruit that hangs lowest, while anthracnose nearly always 

 occurs on the upper surface or on the sides. Fruit affected with 

 anthracnose is perfectly wholesome, and in the early stages the flavor 

 is not affected. The following preventives will be found useful : 



1. Keep the withertip fungus as much reduced as possible dur- 

 ing the summer. 



2. Avoid any treatment that is likely to reduce the foliage of 

 the tree. 



3. When withertip fungus is present in considerable abund- 

 ance, or the foliage of the trees has been considerably reduced from 

 any cause whatever, weekly inspections should be made, beginning 



