- 1. Crinkled and curled
- 2. Leaves coated with
- 3. Splitting
- 4. Fertilizing
- 5. Holes in
- 6. Citrus
- 7. What citrus trees grow well in the
- 8. Premature fruit drying
1. What's causing the leaves of my citrus trees to
be curled and crinkled?
Two Possibilities: Citrus Leaf Miner
Damage — This insect is the maggot
of a tiny fly that lays eggs into the leaves. Maggots hatch from the eggs
and "mine" their way through the leaves causing them to cup and
crinkle. "Squiggly" lines can also be seen in the affected leaves.
This insect is not harmful to the health or fruit production of
established trees. Young citrus trees may benefit from sprays of
horticulture oil which interfere with the fly's ability to lay eggs into
the leaf. Spray each time a new flush of growth appears. Read the
label of oil product carefully, as horticulture oil can burn the leaves
when applied incorrectly. Leaf Miner Damage
Or Aphid Damage – Curled,
distorted leaves can also be the result of aphid insects. These
pests have needle-like mouthparts which pierce the leaves and feed on the
plant sap. They always feed on the newest, most tender growth.
As these leaves mature, they exhibit the damage, but by then the aphids
are long-gone. Aphid damage is mostly aesthetic and can be ignored.
If aphids are detected, they can be easily controlled by forceful sprays
of water or by insecticidal soaps.
2. The leaves of my
citrus tree are covered with black "stuff." Is it hurting my tree?
Sooty Mold — Appears as
a black, sooty growth on the upper side of leaves. Is harmless, but
indicates that an insect was or is present (usually aphids, whiteflies, or
scales). As these
piercing-sucking insects feed on the undersides of the leaves, they
secrete a sticky, clear fluid that drops onto the leaves below.
Sooty mold grows upon this secretion.
3. The fruits on my
citrus tree are splitting and falling off. There are little bugs in
the fruit. What can I do to prevent this?
Water or Varietal Problem. The problem of
splitting fruits usually occurs in the early fall. At this time of
year, the citrus fruits are mature in size and the peel is not expanding.
If heavy rains occur, citrus trees absorb water and force it into the
fruits. The peel cannot expand, and instead splits. The fruit
will begin to decay and attract insects. Splitting fruit is also
associated with young trees and certain varieties.
4. How do I fertilize
Citrus which has been planted
in the ground over four years should be fertilized three times per year:
(January/February, May/June, and October/November) at the rate of one
pound per year of the tree's age (counting from the time it is planted) up
to a maximum of 10 pounds per application. Young trees should receive
between 4 and 6 applications per year at a rate of one pound per year of
age. An 8-8-8 fertilizer that contains slow release nitrogen and
secondary nutrients (particularly magnesium, manganese, copper and boron)
is recommended. Apply the fertilizer to the entire rooting area which
extends from the trunk out to several feet beyond the drip line of the
5. Something is chewing
holes in the leaves of my citrus tree. Will it hurt my tree?
insect — Usually either a
grasshopper or caterpillar. Damage is usually contained to a small
proportion of leaves and should be ignored. The caterpillar is
called an Orange Dog, and is the larval stage of
the beautiful Giant
6. Why do my citrus blooms
drop without setting?
Citrus must be planted 3 to 4
years before it becomes mature enough to set fruit. It may bloom
prolifically, but it will drop its blooms. Even mature citrus sets only a
very small amount of its bloom (less than 1%).
7. What citrus trees grow well in the Florida Keys?
The more tropical citrus fruits like Key
Lime, Tahiti Lime and Pummelo,
all the other citrus varieties do well but are more cold hardy. On
oranges, you may not get good orange color because of the lack of cool
weather, but the fruit is fine. The most important factor when
selecting a citrus for your yard is the root stock - use lemon types
(rough lemon and macrophylla are the best) for our alkaline soils.
have a 5 year old naval orange tree in our yard, and it has begun to bear
the past two or three years. The only problem is, the oranges are
dry when we cut them open. They are beautiful on the outside, but
are pithy and have no juice. What is wrong?
fruit drying (granulation) navel, mandarins, mandarin hybrids, grapefruit
and Valencia fruit sometimes exhibit drying of juice vesicles when harvest
is delayed or when the trees are grown on lemon or other vigorous
rootstocks. The problem varies seasonally and is more of a problem on
larger size or late bloom fruit. Drying appears to be associated with
over-maturity, a lack of water, excessive tree vigor, extended warm,
and/or dry fall weather. Premature fruit drying is also a problem
associated with young trees, a condition that is alleviated with tree
maturity. Refer to EDIS document
in the Home Landscape.
each of the factors listed: rootstock type, was the fruit picked as over
mature fruit, did the tree receive regular watering.
See the links listed below for more