COOPERATIVE EXTENSION WORK IN
AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
AGRICULTURAL EXTENSION SERVICE, UNIVERSITY OF FLORIDA
FLORIDA STATE UNIVERSITY
AND UNITED STATES DEPARTMENT OF AGRICULTURE
H. G. CLAYTON, DIRECTOR
Papaya Insect Control
JAMES E. BROGDON, Extension Entomologist
D. 0. WOLFENBARGER, Entomologist
Sub-Tropical Experiment Station
Fig. 1.-Papaya fruit fly laying eggs.
(Photographs by D. O. Wolfenbarger.)
AGRICULTURAL EXTENSION SERVICE
Papayas hold much interest for many home owners and several
commercial growers in the southern part of Florida. These plants
have been grown in the state for many years and have been
widely publicized at times.
Insects are a limiting factor in the growing of papayas and
should be guarded against constantly, especially from fruit set
until harvest. It is advisable to wait until insects appear before
applying control measures to most crops. However, in areas
where the papaya fruitfly is a problem, preventive control meas-
Fig. 2-Injury caused bTxy pjpaya fuitflx Iarvae.
ures should be taken. Control efforts are directed against the
adult female before she has an opportunity to deposit eggs
inside the fruit (see Figure 1).
PAPAYA FR "ITFLY
The adult fruitfly, sometimes erroneously called a wasp, is
about a half inch long and has an ovipositor as long as the body
proper. This long ovipositor can penetrate the entire distance
through the flesh of the fruit and deposit eggs in the seed-
cavity (Figure 1). Egg-laying may take place when the fruit
is quite small. The larvae-small legless maggots-usually feed
on the seed and lining of the seed cavity (Figure 2).
No spray treatment will destroy the larvae once they are in-
side the fruits. It is suggested that all dropped and prematurely
ripe fruits, as well as small fruits suspected of being infested,
be destroyed to prevent the larvae from developing into adult
The suggested insecticide program is directed at adult fruit-
flies to prevent egg-laying within fruits. A working control
has been obtained where growers apply DDT-sulfur dusts or
sprays at two- to three-week intervals starting soon after the
fruits set. Six to 12 applications may be necessary for satis-
factory control. A 3:,; or 5'; DDT-sulfur dust may be used.
The suggested spray is made by mixing 2 pounds of 50/o DDT
wettable powder "and 8 pounds of wettable sulfur per 100 gallons
It is very difficult or impossible for a person with only a few
plants to get effective control with DIT if nearby neighbors
with papaya plants also do not take proper precautions. He
has to fight his neighbor's fruitflies in addition to his own. Only
if one has many plants are DDT-sulfur treatments suggested.
The person with a few plants can combat this pest by bagging
individual fruits with small paper bags as soon as they set.
The bags may be changed as fruits enlarge.
Fig. 3.--Emergence holes of papaya fruitfly larvae.
This insect is sometimes referred to as the fruit cluster worm,
but is most commonly called papaya webworm. It develops
between fruits in clusters and between fruits and stem of plants
and builds a web (Figure 4). The webworm causes injury to
fruits and stem
--- --- (Figure 5), pro-
F hidingg an en-
trance for the
L fungus disease.
S. can be controlled
by spraying with
l DDT or chlordane
at the rate of 2
pounds of 50';
s we ettable powder
per 100 gallons of
water or 1 ounce
in 3 gallons (about
2 tablespoons per
should be started
when webs are
first noticed or
7 when fruits begin
to set if the web-
worm is prevalent
in the area.
Fig. 4.-Webs and excrement of papaya webw orms. T h e whitefly
adult is a small
white insect which often can be detected by shaking leaves of
the plant, especially young leaves. The young (larval) stages
are flat, scale-like creatures and, except during the first or
active "crawler" stage, are immovably fastened to the plant.
These insects have sucking mouthparts and most of the injury
is caused by the young stages. Sootymold, a black fungus, may
cover leaves, fruits and stem as a result of infestations. This
fungus develops on the sweet, syrupy excretions of immature
The papaya whitefly can be controlled with sulfur sprays or
dusts. The spray
should be mixed
at the rate of 8
pounds of wet-
table sulfur per
100 gallons of
water and applied
when adults be-
Hornworms are '.
of large sphinx
moths and may .
grow to the large
size of about 3
inches or more e
in length. Occa-
tions occur and
large portions of
leaves may be
consumed in a
short period of
Leafhoppers Fig. 5.-Papaya webworn injury.
are very small,
light-green insects with sucking mouthparts. Hornworms and
leafhoppers may be controlled with DDT dusts and sprays as
discussed under webworm and fruitfly.
INSECTS AS VECTORS OF VIRUS I)ISEASES
Virus diseases are another limiting factor in the production
of papayas in south Florida. These viruses are undoubtedly car-
ried by insects, but the exact insects carrying them under Flor-
ida conditions are not definitely known at present.
Insecticides are poisons and should be handled with care.
Always read manufacturer's label on insecticide container as to
usage and cautions. Parathion, which is commonly used for in-
sect control on many plants in Florida, should not be applied
to papaya plants, as it will injure them.