770 
Remedy 
Paris green applied to the under side 
of the leaves. 
Celery or Parsley Caterpillar 
Papilio polyxenes Fab. 
- Family Papilionidae 
Papilio asterias Fab. 
General Appearance 
The most evident forms of this insect 
are the feeding caterpillars, which are 
indeed very striking. The youngest of 
these are noticeably darker with yellow 
spots. When full grown they are yellow- 
ish green with distinct black bands and 
dots on the bodies. If disturbed they 
throw out a forked, orange-colored scent 
organ behind the head, which exhales a 
very pungent and characteristic odor. The 
eggs are about 1 mm. in length, at first 
yellow and later reddish brown in color, 
and flattened at the attached end. The 
adult butterflies are commonly known 
Vig. 1. 
Caterpillar and Chrysalis of the Pars- 
ley Butterfly (Papilio polyxenes Fab.) 
(Original. ) 
as the black swallowtails, 
with yellow markings. The chrysalids 
vary from green to dull gray and are 
more or less mottled. The zebra cater- 
pillar is equally striking in appearance 
but smaller. 
Life History 
The eggs are laid upon the food plants 
from spring to early summer and hatch in 
about ten days. The caterpillars are 
voracious feeders and develop very rapid- 
ly, being ready to form chrysalids in 
about one month after hatching. Chry- 
salids hatch in about two weeks. The 
adults being strong fliers are able to 
scatter their broods over large areas. 
There are several generations a year. 
being black 
feeds also upon carrots, 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
Food Plants 
In many localities this caterpillar is a 
serious pest of celery and parsley, but 
caraway, par- 
snips, dill, fennel and related wild plants. 
Control 
Though the caterpillars may be con- 
trolled by poison sprays on some crops, 
these are not safe for celery and parsley. 
The larvae are so conspicuous as to make 
hand picking one of the best methods of 
control. If care is exercised to collect 
and destroy the first larvae the second 
and more damaging brood will be greatly 
reduced. Concerted action on the part of 
all growers is necessary to bring satisfac- 
tory results. 
Natural Enemies 
The ichneumon parasites, Trogus vul- 
pinus Grav. and TT. exidianator Brulle, 
destroy great numbers of the chrysalids. 
E. O. Essie 
Grasshoppers 
Some species of grasshoppers often 
prove: destructive pests during the early 
part of the season, especially where the 
celery is planted near meadows or other 
habitat of these insects. Where no fowls 
are allowed to run, it is practicable to 
poison the grasshoppers by means of 
wheat bran to which there has been add- 
ed molasses and water and enough Paris 
green to give the mixture a slightly green 
color. | 
PARSNIP LousE. See under Parsnip. 
Tarnished Plant Bug 
This insect while not considered a 
dangerous celery insect, has been known 
to injure the crop in several instances. 
While young this bug is very small, be- 
ing only about one-twentieth of an inch 
in length, of a yellowish or yellowish- 
green color, which changes to a faded 
yellow or dull brown when it is fully 
grown. It works especially where weeds 
abound and on crops that are somewhat 
neglected. As a preventive, keep the 
celery well cultivated and free from 
weeds, and do not allow any trash to 
lie over the ground beneath which the 
insects can pass the winter. Kerosene 
emulsion is moderately effective when 
