THE GRAPE ROOT WORM 229 



this insect may be the cause of grape troubles elsewhere in the state, 

 either at the present time or in the near future, and that because of 

 the semi-concealed nature of its attack the cause of this trouble is 

 not likely to be quickly recognized unless intelligently looked for, 

 this brief discussion of the habits, life-history and means of control 

 of the grape-root worm has been prepared for the grape growers of 

 this state. 



The grape-root Avorm (Fidia viticida) is a native insect which 

 originally fed principally upon wild grape vines and which still attacks 

 them to a limited extent. Shortly after the Civil War instances of 

 damage to cultivated grapes by this insect began to be noted in the 

 upper Mississippi Valley, first in Kentucky and ?»Iissouri and later in 

 Iowa, Illinois, Ohio, Pennsylvania and New York, and in each locality 

 the insect soon became a vineyard pest of prime importance. For the 

 past twenty years, especially, it has been destructively abundant in 

 those states, and is now known to occur from eastern Nebraska and 

 Kansas, Arkansas and northeastern Texas through Iowa, Missouri, 

 Illinois, Indiana, Kentucky and Ohio to southern New York, Con- 

 necticut, Pennsylvania, ^Maryland, the Virginias and northern North 

 Carolina. 



The injury by the grape-root worm is of a dual nature; ttrst, the 

 larvae attack and feed upon the roots of the vines, devouring the root 

 fibre, channeling the larger roots and even eating pits in the main 

 trunk, and second, the adult beetles emanating from these Avorms 

 gather on the leaves and eat holes in the upper parenchyma, leaving 

 chain-like lines on the leaf as a result of this activity. The work of 

 the larvae on the roots is, however, much the more serious form of 

 attack, and the dying out of the vines, such as was observed this 

 year, is the frequent result of it. Old and vigorous vines will with- 

 stand a considerable amount of attack, sometimes until the roots are 

 largely consumed and the half-severed root ends are decayed, pro- 

 vided the soil is rich and is kept in good condition and the new root- 

 fibre are consumed also or conditions are otherwise adverse, the vines 

 become sickly, fail to grow and produce only small fruit clusters, or 

 they even suffer the premature dropping of the leaves and the shrivel- 

 ing up of the fruit, followed by the death of the vine. The attack of 

 the beetles on the leaves is ordinarily not very serious, but in some 

 cases, especially on young plants when the beetles are very numerous, 

 the leaves may be so badly shredded that they discolor and causing 

 a consequent sever setback to the vines. 



The grape-root worm has but a single generation in a year. 

 Winter is passed as three-fourths grown larvae in cells deep in the 

 soil of the vineyard and under the roots. In May these larvae leave 

 their winter cells and feed slightly for three weeks or thereabouts, 

 completing their growth. They then begin to form their pupal cells 

 by rolling and twisting about so as to pack the surrounding soil two 



