THE BEACH PLUM 



11 



The plum curculio {Conotrachelus nenuphar) is a small snout beetle about 

 1 5 inch long, very closely resembling the plum gouger, but slightly larger. 

 It can be distinguished from the plum gouger by the presence of humps on its 

 back. Also, it can fold its 

 snout back under its body, a 

 trick the gouger cannot per- 

 form. The egg-laying punc- 

 tures are cjuite distincti\e. 

 The gouger makes a single 

 round hole; the curculio a 

 hole with a crescent-shaped 

 cut around it resembling" a 

 crescent and star, from which 

 it gets the nickname "Little 

 Turk." The curculio passes 

 the winter in the adult stage 

 under stones, leaves, and 

 other plant debris. It comes 



out of hibernation about blossom time, somewhat later than the gouger, and be- 

 comes active about the time of the shuck spray or a little later, depending largely 

 on temperature. If the temperature reaches 75" on two or three successive days 

 at about shuck time, the curculio becomes very active. 



The female lays her eggs under the skin of the small fruits. The larvae hatch 

 in about a week and feed on the flesh. Such infested fruits drop prematurely. 

 After feeding in the plum about two weeks, the larvae leave and burrow into 

 the soil where they pupate and change to the adult. Four weeks after the larvae 

 enter the soil, the adults emerge with ravenous appetites. They usually lay no 

 eggs but feed on the fruit until cold weather comes, when they hibernate. The 

 curculio can be controlled by thorough applications of lead arsenate at the proper 

 time. 



Figure 10. Plum Curculio Beetles. 

 Notice the pattern on the back, particularly the humps. 



Diseases 



Plum pockets or plum bladders (Fig. 11) is probably the worst disease of 

 beach plums. It is very troublesome in the coastal regions of the state where 

 it attacks both wild and cultivated plums, and damage is often extremely heavy. 

 It seldom appears in other parts of the state. 



Plum pockets is caused by a fungus {Taphrina pruni) very similar in appear- 

 ance and general behavior to that which causes peach leaf curl. It winters over 

 in infected twigs. From these the fungus grows into the central part of. the 

 flower, the ovary, which later becomes the fruit. .Some of the fungus threads 

 grow to the surface of the twig and produce spore-forming bodies which dis- 

 charge numerous spores. It also attacks young leaves causing them to curl, turn 

 yellow, and drop. Infected plums become swollen, misshapen, and hollow, with 

 no seeds; hence the name, plum bladders. Finally they turn dark brown or 

 black and become hard so that they rattle against any hard surface. In this 

 condition they hang to the tree only two or three days, then drop. This drop- 

 ing takes place the latter part of June. This disease can be controlled b\- spray- 

 ing with dormant-strength lime-sulfur. Where possible, diseased and dead 

 twigs should be cut out and burned. 



