AGRICULTURAL CROP DISEASE MANAGEMENT 2025/2026
QUESTIONS WITH SOLUTIONS GRADED A+
✔✔What is a necrotrophic lifestyle? - ✔✔Pathogen derives it's nutrients from dead or
dying tissues Ex. Soybean white mold
✔✔What does monocyclic refer to? - ✔✔Pathogen completes one cycle of life
(infection) during a growing cycle
✔✔What does polycyclic refer to? - ✔✔Pathogen produces more than one infection
cycle per growing season
✔✔What is a pathogen effector? - ✔✔Proteins expressed by plant pathogens to help
with infection of specific species
✔✔What is a plant receptor? - ✔✔Protein required to identify the pathogen and begin
immune response
✔✔What is the hypersensitive response? - ✔✔Rapid, localized cell death response that
is triggered by infection. This response helps prevent the further spread of biotrophs
and is an early line of defense against infection.
✔✔What are differentials? - ✔✔A series of wheat lines with known resistant genes to
characterize the pathogenic reaction or virulence pattern of a stem rust isolate
✔✔Describe the infection rating scale. - ✔✔0-4. (0-2+ is low infection type or IT) (3 and
4 are high IT) (; are used to identify specks) The IT then corresponds to High or Low
response. Four correlate to a race code.
✔✔What are some merging diseases? - ✔✔Red corn rot of soybean (Calonectria
ilicicola) appears as red stems
✔✔What is FHB? - ✔✔Fusarium head blight (scab) of wheat caused by Fusarium
graminearum (fungus). Appears as bleaching of spikelets and orange spores may form
on spikelets.
✔✔What is tar spot? - ✔✔fungal disease of corn causing tar like black spots on leaves
(Phyllachora maydis)
✔✔What is NCLB? - ✔✔Northern corn leaf blight caused by fungus (Exserohilum
turcicum) and causes cigar-shaped gray like lesions on leaves
✔✔What is late blight? - ✔✔Oomycete that affects potatoes (Phytophthora infesting)
, ✔✔What is white mold? - ✔✔Fungus that affects soybeans (Scleortinia sclerotiorum)
causes white fuzzy mold growth on stems and leaves
✔✔What is stem rust? - ✔✔Fungus that affects cereal crops (Puccinia graminis) causes
red pustule spores on stems. Alternate host of barberry
✔✔What are the different types of rusts? - ✔✔Stripe rust (yellower) leaf rust (orange)
stem rust (red-brown)
✔✔What is WSMV? - ✔✔Wheat streak mosaic virus causing chlorosis and lightening
along leaves, vectored by wheat curl mites
✔✔What is powdery mildew? - ✔✔fungus that affects wheat and barley (Blumeria
graminis) causes white powdery growth on leaves and stems
✔✔What is STB? - ✔✔Septoria Tritici Blotch/ Septoria leaf spot (Zymoseptoria tritici)
fungus that affects wheat that causes elliptical tan brown lesions with a yellow halo may
have speckled appearnence. white oozy may appear from fruiting bodies.
✔✔What is BLS? - ✔✔Bacterial leaf streak that affects wheat (Xanthomonas campestris
vp. Undulosa) causes water soaked lesions that may ooze honey like exudates. May
cause black chaff of head
✔✔What is tan spot? - ✔✔Fungal disease (Pyrenophora trice-repentis) that affects
wheat and causes tan, eyespot lesions surrounded by a yellow halo and may cause red
smudge on kernels
✔✔What is ergot? - ✔✔Fungal disease (Claviceps purpurea) that affects wheat and
causes honeydew ooze on wheat heads, later sclerotia develop on kernels and look
black
✔✔What are fungicides? - ✔✔Products of natural or synthetic origin which act to protect
plants against fungi or eradicate their establishment (targets fungi, cercozoa, and
oomycota)
✔✔Describe the fungal cell wall - ✔✔Has chitin (present in insects) and ergosterol (not
present in animals or plants)
✔✔Are oomycetes true fungi and what is their cell wall made of? - ✔✔No, kingdom
Protista, contain cellulose
✔✔What are some examples of oomycetes? - ✔✔Phytopthora (late blight) pythium
(damping off) pseudoperonospora (downy mildew)
QUESTIONS WITH SOLUTIONS GRADED A+
✔✔What is a necrotrophic lifestyle? - ✔✔Pathogen derives it's nutrients from dead or
dying tissues Ex. Soybean white mold
✔✔What does monocyclic refer to? - ✔✔Pathogen completes one cycle of life
(infection) during a growing cycle
✔✔What does polycyclic refer to? - ✔✔Pathogen produces more than one infection
cycle per growing season
✔✔What is a pathogen effector? - ✔✔Proteins expressed by plant pathogens to help
with infection of specific species
✔✔What is a plant receptor? - ✔✔Protein required to identify the pathogen and begin
immune response
✔✔What is the hypersensitive response? - ✔✔Rapid, localized cell death response that
is triggered by infection. This response helps prevent the further spread of biotrophs
and is an early line of defense against infection.
✔✔What are differentials? - ✔✔A series of wheat lines with known resistant genes to
characterize the pathogenic reaction or virulence pattern of a stem rust isolate
✔✔Describe the infection rating scale. - ✔✔0-4. (0-2+ is low infection type or IT) (3 and
4 are high IT) (; are used to identify specks) The IT then corresponds to High or Low
response. Four correlate to a race code.
✔✔What are some merging diseases? - ✔✔Red corn rot of soybean (Calonectria
ilicicola) appears as red stems
✔✔What is FHB? - ✔✔Fusarium head blight (scab) of wheat caused by Fusarium
graminearum (fungus). Appears as bleaching of spikelets and orange spores may form
on spikelets.
✔✔What is tar spot? - ✔✔fungal disease of corn causing tar like black spots on leaves
(Phyllachora maydis)
✔✔What is NCLB? - ✔✔Northern corn leaf blight caused by fungus (Exserohilum
turcicum) and causes cigar-shaped gray like lesions on leaves
✔✔What is late blight? - ✔✔Oomycete that affects potatoes (Phytophthora infesting)
, ✔✔What is white mold? - ✔✔Fungus that affects soybeans (Scleortinia sclerotiorum)
causes white fuzzy mold growth on stems and leaves
✔✔What is stem rust? - ✔✔Fungus that affects cereal crops (Puccinia graminis) causes
red pustule spores on stems. Alternate host of barberry
✔✔What are the different types of rusts? - ✔✔Stripe rust (yellower) leaf rust (orange)
stem rust (red-brown)
✔✔What is WSMV? - ✔✔Wheat streak mosaic virus causing chlorosis and lightening
along leaves, vectored by wheat curl mites
✔✔What is powdery mildew? - ✔✔fungus that affects wheat and barley (Blumeria
graminis) causes white powdery growth on leaves and stems
✔✔What is STB? - ✔✔Septoria Tritici Blotch/ Septoria leaf spot (Zymoseptoria tritici)
fungus that affects wheat that causes elliptical tan brown lesions with a yellow halo may
have speckled appearnence. white oozy may appear from fruiting bodies.
✔✔What is BLS? - ✔✔Bacterial leaf streak that affects wheat (Xanthomonas campestris
vp. Undulosa) causes water soaked lesions that may ooze honey like exudates. May
cause black chaff of head
✔✔What is tan spot? - ✔✔Fungal disease (Pyrenophora trice-repentis) that affects
wheat and causes tan, eyespot lesions surrounded by a yellow halo and may cause red
smudge on kernels
✔✔What is ergot? - ✔✔Fungal disease (Claviceps purpurea) that affects wheat and
causes honeydew ooze on wheat heads, later sclerotia develop on kernels and look
black
✔✔What are fungicides? - ✔✔Products of natural or synthetic origin which act to protect
plants against fungi or eradicate their establishment (targets fungi, cercozoa, and
oomycota)
✔✔Describe the fungal cell wall - ✔✔Has chitin (present in insects) and ergosterol (not
present in animals or plants)
✔✔Are oomycetes true fungi and what is their cell wall made of? - ✔✔No, kingdom
Protista, contain cellulose
✔✔What are some examples of oomycetes? - ✔✔Phytopthora (late blight) pythium
(damping off) pseudoperonospora (downy mildew)
