Sept. 1894.] 



INJURIOUS INSECTS AND FUNGI. 



47 



The Mangel Fly (Anthomyia Betoe). 



Several complaints were received in May of attacks of the 

 mangel-fly. These attacks were unusually early. Though the 

 mangel-plants were very forward, in common with most vegeta- 

 tion, the date of the appearance of the larvae within the tissues 

 of the leaves was somewhat abnormal. Many were found before 

 the plants had been singled, and it was feared that a bad 

 attack was imminent. But seasonable showers forced the 

 plants along rapidly, and the climatic conditions were appa- 

 rently not suitable to the spread of this pest, so that it has 

 not caused much harm this season. 



It was observed in connection with this attack that the flies 

 laid eggs upon the weed known as " fat hen " or " goosefoot," 

 Chenopodium album, L., which was growing abundantly among 

 mangel-plants on land that had been heavily manured with 

 farm-yard manure. These weeds were carefully watched, but 

 it could not be discovered that the larvae hatched from the 

 eggs attacked the leaves, nor could it be seen what became of 

 the larvae. It may be remarked that " fat hen " is a common 

 weed in farm-yards and upon the sides of mixens. 



Pear and Apple Scab (Fusidadium dendriticum, Fuchel), 



In some seasons pears and apples in orchards and gardens are 

 pitted with small scars or scabs. These not only affect the 

 appearance of the fruit, but tend to reduce its size and make it 

 more or less unhealthy. The scabs vary in size. At first they 

 are not larger than a pin's head ; in some cases they become as 

 large as a small pearl button. Upon examining them micro- 

 scopically it will be seen that there are thick congeries of 

 mycelial threads of a fungus running through the upper cells of 

 the fruits. These threads are at first colourless, and as they 

 mature they become reddish-brown. From these mycelial centres 

 conidia are produced, oval and colourless at first, but becoming 

 darker later on. 



The hyphae of the fungus pervade the tissues of the fruits 

 near them, and new centres of disease are created by spores 

 from the conidia. 



This fungus, which is known as Fmicladium dendriticum, 

 Fuckel, or Cladosporium dendriticum, Wallroth, belonging to 

 the family Hyphomycetes, is found also upon the leaves of apple 

 and pear trees, and in this form it causes unhealthiness to the 

 whole system of the tree. 



Pear trees have been considerably affected this year by the 

 Fmicladium dendriticum, especially those trees of the variety 

 known as Williams Bon Chretien. 



