Plant Diseases Flashcards
What are pathogens?
Pathogens are microorganisms which cause disease. They include bacteria, viruses, protists and fungi.
What can insects (pests) do to plants?
Insects (pests) can infect plants and reduce their growth.
What effect do plant diseases have on the food chain?
Plant diseases don’t only impact plants but affect the whole food chain. Diseases affecting food crops can have a detrimental effect on humans, as seen in the Irish potato famine of 1850.
What diseases can pathogens cause in plants?
Pathogens can cause plant diseases that lead to reduced plant growth and productivity.
What is rose black spot?
Rose black spot is a fungal disease which affects plants. It causes reddish-black spots to appear on the leaves and causes the leaves to turn yellow and fall off.
How does rose black spot affect plant growth?
The discolouration means that the plant cannot carry out as much photosynthesis so it cannot grow very well.
How is rose black spot spread?
Rose black spot is spread between plants when the fungus lands on a plant after being blown by the wind or floating along rivers or streams.
How can the spread of rose black spot be prevented?
The spread of rose black spot can be prevented through the use of fungicides and by cutting off diseased leaves from the plant.
What is tobacco mosaic virus?
Tobacco mosaic virus is a disease which affects plants and causes discolouring of leaves.
How does tobacco mosaic virus affect plant growth?
It reduces the amount of pigment in the leaves, meaning the plant cannot photosynthesise as efficiently, which results in stunted growth.
How is tobacco mosaic virus spread?
Tobacco mosaic virus is spread when the leaves of a healthy plant physically touch a plant with TMV.
What is the effect of aphids on plants?
Aphids feed on the sap within plant stems, reducing the amount of glucose available to the plant, which slows growth and can lead to plant death.
What happens when plants suffer from nitrate deficiency?
Without sufficient nitrates, plants have stunted growth and yellowing leaves because nitrates are needed to build proteins including chlorophyll.
Why do plants with nitrate deficiency have yellowing leaves?
Nitrates are needed to make chlorophyll. Without chlorophyll, plants cannot photosynthesise, leading to stunted growth and yellowing leaves.
What is the effect of magnesium deficiency on plants?
Plants with magnesium deficiency have yellowing leaves because magnesium is needed to make chlorophyll.
Why do plants with magnesium deficiency have yellow leaves?
Without enough magnesium, plants cannot make enough chlorophyll, reducing photosynthesis and leading to yellow leaves and stunted growth.
What are some symptoms of plant diseases?
Symptoms of plant diseases include stunted growth, abnormal stems or leaves, growths, decay, spots on leaves, discolouration, and the presence of pests.
How can gardeners identify plant diseases?
Gardeners can identify plant diseases by looking up symptoms in a manual, taking infected plants to a lab, or using testing kits with monoclonal antibodies.
What are some common symptoms of plant diseases?
Common symptoms include stunted growth, abnormal stems or leaves, growths, decay, spots on leaves, discolouration, and pests.
How can gardeners use monoclonal antibodies to identify plant diseases?
Testing kits with monoclonal antibodies can help gardeners detect specific pathogens in infected plants.
How do plants defend themselves against infection or being eaten?
Plants defend themselves with physical chemical and mechanical defences.
What are physical plant defences?
Physical defences form barriers that prevent pathogens from entering the plant.
What are examples of physical defences in plants?
Examples include a thick layer of bark on trees cell walls made of cellulose and a tough waxy cuticle on leaves.
What chemical defences do some plants have?
Some plants produce antibacterial chemicals which kill bacteria that enter the plant.
