Fly strike susceptibility
The provincial veterinary and dairy diagnostic laboratory has recently received inquiries about myiasis, a condition commonly known as fly strike.
“In Saskatchewan, fly strike is caused by the blowfly, a member of the Calliphorinae family,” said Shelagh Copeland, a veterinary pathologist at the provincial lab.
A blowfly can lay eggs in decomposing matter such as a carcass, or in decomposing matter in a live animal, such as an animal with dermatitis, a wound or soiled and matted hair or wool.
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Blowflies lay hundreds of light-yellow eggs in the carcass, wound or soiled area. The eggs produce white or pale-yellow maggots in eight hours to three days, depending on the temperature. Feeding on the decomposing matter and often invading healthy tissue, the maggots become fully grown in two to 19 days. Then they drop off to complete their cycle in the ground, or in dry areas of the carcass or live animal.
The area of fly strike is moist and brown with an obvious odor. The maggots may not be noticeable unless the hair is parted and the skin or wound is inspected closely, including any small holes or cavities in which the maggots could be living.
The lesion and the parasites irritate their host. Animals don’t feed properly, becoming weak and poor. Death is usually caused by septicemia or toxemia.
Sheep most often die from fly strike because of their wool, but fly strike can also affect any animal with wounds or soiled, matted coats including horses, cattle or dogs.
“The most important thing to remember about fly strike is that blowflies don’t lay their eggs in normal, undamaged, clean hair coats,” said Copeland.
Debilitated animals, such as aging dogs or defective calves, or those that have open wounds or sores are most at risk.
Treatment of fly strike aims to kill maggots in the lesion. It requires clipping and cleaning, as well as destroying and removing all larvae. Dressings containing larvicides and antiseptics should be applied. Copeland said directions for insecticides should be followed carefully and the insecticides used judiciously as they can be harmful, especially in a weak animal.
If the animal is depressed or showing other signs of illness, a veterinarian should be consulted. The underlying cause of the fly strike needs to be treated as well.
– Saskatchewan Agriculture
Artificial seeds
Guelph researchers are creating artificial herbal seeds to capitalize on the $500 million North American market for herbs. French tarragon (a culinary herb), peppermint (used for tea that calms stomach indigestion) and lemon-scented geraniums (found in potpourri and perfumes) – which are normally propagated by cuttings – are their initial targets.
“We are not trying to make the artificial seed the same as a true seed,” said horticultural scientist Tissa Senaratna. “We are trying to make it better.”
In the first project of its kind in Canada, Senaranta and colleagues Praveen Saxena and Massimo Sanago are creating artificial seeds from the tissues of herbal plants.
Artificial seeds have several advantages over cuttings. They survive better during shipping and help reduce shipping costs. Because they’re grown in a disease-free culture, they’re free of pathogens and can eliminate the expense and lost time associated with quarantine. They also permit mass production of hybrid plants.
To create whole plants from small pieces of plant tissue, researchers cut a two-millimetre piece of stem or leaf from the plant, sterilize it to kill bacteria and place it in a growth medium containing plant-growth regulators.
The growth regulators cause some cells to act like fertilized eggs rather than normal plant cells. They grow into embryos, much like they would in a seed pod. With the help of certain nutrients and growth regulators, they ultimately develop like a seed.
In the late 1980s, Senaratna was co-inventor of a process to dry these “artificial” seeds so they could be practically packaged, shipped or stored, instead of shipping a whole plant or cutting.
In addition, he and Saxena are working on the creation of an artificial seed coat – a nutrient-rich coating to cover the somatic embryo and enable enhanced growth. It will also protect seed from rigorous and potentially damaging commercial planting techniques.
– University of Guelph
