33 



Insects 



Last summer's dry weather, while checking some of the fun- 

 gous diseases, may have lowered the resistance of plants to a de- 

 gree where certain insects became an unusual menace. 



Aphid 



Both Japanese and German Iris have been hosts to the aphid 

 Anuraphis Tulipae Boyer during the past season and have re- 

 quired treatment with Black-Leaf-40 and soap. This sucking 

 insect feeds on the upper parts of leaves as well as on the base 

 near the growing point, often below the soil surface. 



Verbena Bud-Moth 



In August two insects destructive to the seeds of valuable 

 crosses were reported at work in the Iris garden. One of these, 

 the Verbena bud-moth, Olethreutes hebesana Walker, was first 

 noted in its pupal stage. The brown pupa case projects from a 

 black-ringed hole in the seed pod, where the larvae have been 

 feeding for about three weeks. Three days after emergence of 

 the adult, the eggs are desposited on the pod surface. The 

 hatched larvae enter the pod and feed on the seeds until ready 

 to pupate. As there are at least four generations during the sea- 

 son, several applications of an insecticide such as arsenate of lead 

 should be made, beginning soon after the pods begin to form. 

 The insect overwinters as larvae or pupae in cocoons on the leaves 

 or within seeds. 6 It has been widely reported not only as a pest 

 of Iris, but as a " general feeder " on plants. 



Weevil 



The other insect observed attacking Iris seeds was identified by 

 Dr. K. F. Chamberlain, assistant state entomologist, as the weevil 

 Mononychus vulpe cuius. This insect tunnels through the seeds, 

 eating out the embryo and leaving of each seed only a thin ring. 

 At the end of a tunnel which sometimes extends through a whole 

 row of seeds, the small dark weevil may be found with its flat 

 disk-shaped body fitting snugly into the last seed it has mutilated. 

 This pest has been commonly found in the seed pods of native 

 Blue Flag, according to Dr. Chamberlain, but its occurrence on 



6 Ries, Donald T. Two Iris Insects. Bull. Am. Iris Soc, 32: 27-47. 

 Jl 1929. 



