Questions and CORRECT Answers
What are fungi and oomycetes fine, threadlike structures (hyphae) that form a network or mass
are composed of: (mycelium) growing on or through their host
as tiny, often microscopic, seed-like spores...fungi can also
How do fungi and oomycetes
spread as sclerotia or rhizomorphs, which often are large
spread?
enough to be seen with the naked eye
What are rhizomorphs? rootlike or cordlike masses of hyphae
What are sclerotia? compact masses of hyphae
If they are large enough to be seen with the naked eye or hand
What can help to identify
lens, mycelia, mass spores and spore forming structures can help
pathogen species?
with identification
mildews and sooty molds (fungal mycelia and spores), rusts
Visible structures of fungi
(orangish spores), and characteristic conks and mushrooms
include:
(spore forming structures)
rhizomorphs, sclerotia and some types of spores survive for long
periods in or on plants or soil
How long do rhizomorphs,
sclerotia and some types of
they can be spread by soil movement, machinery, water, wind, or
spores survive? How do they
almost anything they come in contact with
spread? How can they become
active?
Where conditions are suitable, the pathogens can inflect plants
and cause disease
mistletoes are parasitic plants that grow their roots inside of trees
What are mistletoes and what
kind of symptoms do they
disease-like symptoms include distorted growth, decline, and
cause?
dieback.
true (leafy) mistletoes have green leaves and infect both conifers
and oaks
Examples of mistletoes:
dwarf mistletoes infect only conifers and are serious pests of
western forests
, What are bacteria? are microscopic, one-celled organisms
must remain in contact with the host organism or plant debris in
Importance of bacteria
order to survive since they do not produce spores that can
remaining in contact with host:
survive adverse environmental conditions
by splashing water, insects, or people moving infested plants or
soil
How are plant-infecting bacteria
spread? bacteria must enter plants through natural openings or wounds,
such as when bacteria-carrying (vectoring) insects feed on
plants
viruses are noncellular submicroscopic pathogens
plant viruses can stunt, discolor, or deform plant parts or entire
plants, but viruses rarely kill woody plants and sometimes no
What are viruses?
symptoms arise
require a living host cell to reproduce and generally do not
survive very long outside of living tissue
spread by aphids, leafhoppers (including sharpshooters), or
other plant feeding insects
How are viruses spread? Is there
treatment for viruses? once infected, plants usually remain infected during its entire
life...there is no treatment in the field to cure most plants that are
virus infected
often difficult, microorganisms or noninfectious conditions that
cause disease are often not visible to the naked eye, disease
Diagnosing disease causes: symptoms are often variable and when you discover the problem
it is already too late since initial key symptoms are not present
any longer
know the normal appearance of plant species, examine infected
Tips on diagnosing the causes of
plant parts, use tools that will aid in diagnosing and seek
plant problems:
professional help as needed
animals that lack backbones (vertebrae) and include insects,
mites, nematodes and snails
What are invertebrates?
cause damage mostly by feeding on the plant
Two main invertebrate chewing (pincerlike) mouthparts or sucking (straw-like) mouth
mouthparts: parts
beetles, caterpillars, (larvae of butterflies and moths), sawflies (a
Chewing pests include:
subgroup of wasps), and snails and slugs
mites and insects such as aphids, true bugs, and scales
Common sucking insects
include: commonly discolor or distort leaves and shoots, but they do not
typically make obvious holes in plants or solid tissues
during both their adult and immature stages
When can invertebrates cause
feeding damage? others such as moths, damage plants only as immatures because
the adults feed little or not at all
an egg, although in some species the eggs hatch inside the adult
Most invertebrates hatch from?
female