Floriculture Disorders

1
Floriculture Disorders

• Eddie McKie
• Georgia
• February, 2007

2
APHIDS

• Small (up to ¼) soft-bodied insects.
• The characteristic feature that distinguishes
  aphids from other insects are the tail pipes
  (called cornicles) which extend from the rear of
  their abdomen.

3
FUNGUS GNATS

• Adult fungus gnats are about 1/8 to 1/10 inch
  (2.5 mm) long, grayish to black, slender,
  mosquito-like, and delicate with long legs,
  antennae and one pair of wings.

4
LEAF MINER

• Insect larvae that feed inside a leaf, between
  the upper and lower surfaces.

5
MEALY BUG

• Mealybugs derive their name from the white, waxy,
  mealy secretions that cover their bodies.

6
SCALE

• Either soft scales or armored scales
• Covered with waxy shell for most of their life
  which protects them from predators or insecticides

7
SLUG

• Slugs are gastropod mollusks without shells or
  with very small internal shells, in contrast to
  snails.

8
SPIDER MITE

• To the naked eye, spider mites look like tiny
  moving dots
• Adults have eight legs and an oval body, with two
  red eyespots near the head end of the body.

9
POWDERY MILDEW

• Infected plants will display white powder-like
  spots on the leaves and stems.
• The fungus is favored by periods of high relative
  humidity or site conditions that promote a more
  humid environment

10
THRIP

• Thrips are small (1/8 long) and narrow-bodied
  insects commonly found feeding on leaves and
  stems.
• The presence of thrips gives a splotchy
  appearance to leaves.

11
WHITEFLY

• Adults are less than 1/8 long and, like their
  name suggests, have white wings with pale yellow
  bodies.
• Adult whiteflies congregate above and under leaf
  surfaces, and disperse in clouds when disturbed.

12
BLACKLEG

• Plants with blackleg are stunted and have a
  stiff, erect growth habit.
• Foliage becomes chlorotic and the leaflets tend
  to roll upward at the margins.
• Stems of infected plants exhibit an inky black
  decay. The base of the stem is often completely
  rotted.
• In relatively dry soil, only the pith may show
  blackening.

13
BLACK SPOT

• Round to irregular black splotches with fringed
  margins are quite obvious, mostly on upper leaf
  surfaces.
• Round to irregular black splotches with fringed
  margins are quite obvious, mostly on upper leaf
  surfaces. Leaf yellowing develops around these
  black spots, with defoliation of these infected
  leaves common. Round to irregular black splotches
  with fringed margins are quite obvious, mostly on
  upper leaf surfaces. Leaf yellowing develops
  around these black spots, with defoliation of
  these infected leaves common. Leaf yellowing
  develops around these black spots, with
  defoliation of these infected leaves common.

14
BOTRYTIS

• Botrytis is by far the most common fungal disease
  encountered under cool, humid conditions,
  particularly were crops are grown at a high
  density with limited air movement.

15
DAMPING OFF

• A common fungal disease that attacks seedlings,
  weakening the stems right at the soil level.
  Infected seedlings usually die.

16
MOSAIC VIRUS

• Characterized by the presence of intermingled
  patches of normal and light green or yellowish
  colored plant tissue.

17
ODEMA

• appears as small, sometimes corky blisters which
  form on the lower surface of leaves or needles.
• These blisters may eventually harden to form
  white, tan, or brown wartlike corky bumps on the
  lower leaf surface.

18
COLD WATER DAMAGE

• Often begins with halo spots of the leaves
  caused by overhead watering with cold or cool
  water.

19
IRON CHLOROSIS

• Iron chlorosis is a yellowing of plant leaves
  caused by iron deficiency that affects many
  desirable landscape.
• The primary symptom of iron deficiency is
  interveinal chlorosis, the development of a
  yellow leaf with a network of dark green veins.

20
BERMUDAGRASS

• Bermudagrass is creeping perennial warm-season
  grass. Bermudagrass spreads by both rhizomes and
  stolons.
• The leaves of bermudagrass are folded in the
  bud, and the sheath is strongly compressed.
• The leaf is short, approximately 1/8 inch wide
  with rough edges.
• The roots of bermudagrass are deep and fibrous
  allowing it to be highly drought tolerant.
• The stolons root at the nodes forming a thick
  dense mat.
• The seedhead of Bermudagrass consists of 3 - 7
  finger-like spikes.
• Common bermudagrass can spread by seed.

21
CRABGRASS

• Crabgras is a low-growing summer annual that
  spreads by seed and from rootings of nodes that
  lie on the soil.
• It may grow upright to a height of 2 feet. It
  will not tolerate close mowing as well as smooth
  crabgrass.
• True leaves are generally 3 inches long and hairy
  on the upper surface of the leaf and leaf sheath.
  
• The branches are l about 2 to 5 inches at the end
  of the stalk.

22
NUTGRASS

• Nutgrass has yellow-green, wide-bladed leaves
  that are smooth and shiny or waxy on the upper
  side.
• Nutgrass grows 1-3 feet tall if not mowed.
• Yellow and purple varieties

23
OXALIS

• The leaves are divided into three to ten or more
  round, heart-shaped or lanceolate leaflets,
  arranged in a whorl with all the leaflets of
  roughly equal size.
• The majority of species have three leaflets in
  these species, the leaves are superficially
  similar to those of some clovers