BRISTLY ROSE-SLUG (Cladius isomerus).
The larva, yellow green with a
dark stripe down the back and stiff hairs, both skeletonizes the
leaves and eats holes through them. There may be several generations a
season, and slug damage in late summer is probably from this species.
It winters in brown papery cocoons in garden trash.
CURLED ROSE SAWFLY (Allantus cinctus).
The greenish larva, with grayish sides and legs, feeds from a coiled position along the leaf edge,
consuming all leaf tissue. It enters the pith of rose canes through pruning
cuts and pupates there. There are 2 generations.
Control. All rose sawflies can be readily controlled by spraying or dusting foliage with DDT, lead arsenate, or rotenone. To reduce injury from
the curled rose sawfly, avoid fall pruning when the wood does not callus
quickly and prune out infested canes below the insect as soon as possible.
It may be wise to paint large pruning cuts, but I never have time.
Diseases with an overgrowth of tissues in a limited area are commonly
APPLE SCAB (Ventuna inaequalis).
This is the top-ranking apple disease,
ruining the crop in a rainy season unless a carefully timed spray
schedule is carried out. The fungus winters in dead leaves on the ground
and in wet spells in spring shoots out spores which are carried by wind
to buds, blossoms, or young leaves overhead. Dark spots on blossoms are
followed by dropping of young fruit. Leaves have sooty areas, slightly
domed, and bear olive-brown conidia which are splashed by rain to other
foliage and fruits. Fruit spots are small, more or less raised, dark olive;
but as the fruit grows they rupture, leaving a white rim around a dark
velvety center; still later the dark mycelium and spores disappear and
the spot is raised, corky, tan in color. When spots are too numerous, the
Control. Sulfur is rather generally used, often combined with Fermate,
starting a week after the delayed dormant spray and continuing weekly
through petal fall and then somewhat less often. Scab control is a job
for the orchardist and not the backyard grower. There is a warning
service which tells farmers when old leaves are ready to shoot their
spores so that the first spray can be applied in time. Captan, Phygon,
glyoxalidine, and mercury compounds are coming to have a place in scab
PECAN SCAB (Cladosporium effusum).
The fungus attacks pecan and
hickory rather generally. Leaves turn black and fall; nuts have
small circular spots which grow together until the whole nut is black
and often drops.
Control. Jar branches to make diseased nuts drop, then clean up. Spray
with low-lime bordeaux when leaves are 1/4 to 1/2grown, after pollination,
and twice more at 3- to 4-week intervals. Varieties Moore and Money-
maker are rather resistant.