10 



MASS. EXPERIMENT STATION BULLETIN 422 



Figure S. Plum Gouger. 

 Note smoothness of gouger's back in com- 

 parison with roughness of plum curculio. 



Photo by R. L. Coffin. 



Insects 



The beach plum is beset by a number of insects and diseases which, if not 

 controlled, cut down the crop and detract from the value and appearance of the 

 fruit. In the following descriptions only broad general control measures are 

 given. For detailed instructions, see the spray chart on page 15. 



The plum gouger {Anthonomous scutellaris) is undoubtedly the worst insect 

 pest of the beach plum. The adult is a small dun-colored snout beetle less 



than 1/5 inch long, often described 

 as looking like a baby elephant. The 

 adults are said to come out of winter 

 quarters early in the spring before 

 the blossoms open and feed on the 

 opening buds and leaves. Shortly after 

 the fruit has set, the beetles feed on the 

 pulp through small holes made in the 

 skin. The female lays her eggs singly 

 in cavities which she gouges in the 

 fruit with her snout. When the eggs 

 hatch, the larvae burrow into the pit 

 where they feed on the kernel till 

 full grown. The pupal stage is passed in the pit. Before changing to a pupa, 

 the larva eats an exit hole through the hard shell of the pit to provide for the 

 escape of the beetle. The adults emerge in late August or early September, eat 

 little, and soon go into hibernation under trash in the vicinity. Infested fruits 

 do not drop but ripen prematurely. The life history of this insect shows why, 

 as has sometimes happened, the grower sells plums thinking there is nothing 

 more wrong with them than a "sting" or two on the surface, and later the custo- 

 mer complains that the plums are wormy. Any grower who values his repu- 

 tation must be careful about selling "stung" plums. Spraying before bloom 

 has been the standard recommendation for control. However, experimental 

 sprays of lead arsenate in 1942 and 

 1943 were not successful in controlling 

 this pest. 



The tent caterpillar {Malacosoma 

 americana), a very common pest, is 

 probably known by most growers. The 

 eggs, which occur in brown masses, 

 particularly on twigs of the wild cherry, 

 hatch early in the spring when the 

 first buds open. The young larvae, or 

 caterpillars, soon make a silken nest 

 in which they live in a colony and 

 which they enlarge as they grow. They 

 leave the nest to feed. They are very 

 voracious eaters and will strip large 

 branches or even whole trees of leaves 

 in a short time if not controlled. The 

 full-grown caterpillar is about two 

 inches long, black with a light stripe 

 down its back, and covered with 

 fine yellow hairs. They are easih' 



controlled bv spraving or dusting with Figure 9. Tent Caterpillar's Nest 



' on Beach Plum. 



lead arsenate. Photo by Bertram Tomlinson. 



