THE SUGAR-CANE LEAFHOPPER. 7 
SYMPTOMS OF LEAFHOPPER INJURY. 
The presence of the pest on the plantations was noticed first by 
the appearance of a sooty black covering on the lower leaves of the 
eane plant. This black covering became known. as smut. It is a 
fungous growth and finds a medium for development in the trans- 
parent, sticky fluid secreted by the leafhoppers during their feeding 
on the plant. This secretion is commonly known as honeydew. 
The black smut or fungous growth in the honeydew secretion of 
the leafhopper and the red discoloration about the openings to the 
ege chambers in the midribs of the leaves are the most pronounced 
symptoms of the work of the 
leafhopper on cane. 
In the case of heavy infesta- 
tion a further result is the 
appearance of the plant as a 
whole. The leaves on which the 
insects have been feeding de- 
velop a yellowish appearance, 
and as the work of the insects 
progresses they become dried 
and resemble the fully matured 
lower leaves of the plant. This 
premature death of the leaves 
is due to the excessive amount 
of juice extracted for food. As 
long as the cane plant is able to 
produce new leaves its life is 
not actually in danger, the in- 
jury being a check to the growth 
and indicated by the small, 

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shortened joints in the stalk. Fic. 1.—The sugar-cane leafhopper (Perkinsiella sac- 
Leaves thus prematurely rip- charicida): a, Adult female, much enlarged; }, 
ovipositor, greatly enlarged. (After Kirkaldy.) 
ened do not drop away from 
the stalk at the junction of the sheath, as is the case under norma 
conditions, but break and hang down at the junction of the leaf to 
the sheath, leaving the sheath still wrapped about the stalk. Leaves 
in such a condition remain green for some time, attached to the 
sheath by the midrib, and an attempt to strip the cane results in 
leaving the sheaths still adhering to the stalk and: wrapped about it. 
In the last stages of an attack, when the plant is actually overcome 
by the pest, the young unfolded leaves at the top do not appear 
to have the vitality to unfold and the ‘‘bud”’ gradually dies out. At 
this stage the normal growth of the plant ceases. Many plants in 
83327°—Bull. 93—11——_3 
