Mite my deck be edible?
Q i have a power cruiser moored in a marina. in the sunshine, the boat is covered in tiny red mites/ spiders (which, when squashed, leave a bright red mark). at night, or in rainy weather, where do they go to, and what do they eat? i am concerned that it might be my teak deck as there is no vegetation nearby. Sarah Higginson, by email SARAH BROWN REPLIES: The red spider mite (Tetranychus urticae), a relative of the spider, is a sap-sucking arachnid and, due to its tiny size, is unlikely to be able to access the limited sap in your teak decks and cause damage. They will probably have been introduced to your boat by larger passing insects or on the wind if you are close to trees or productive areas such as crops or greenhouses.
They will thrive in the dry conditions of your decks, and you may find batches of their eggs in protected nooks and crannies. When conditions are cooler and more damp (at night, or when it rains), they will move into more sheltered local hideouts, under canopies, in tiny cracks in the deck or behind kit etc. A limited few will get washed over the side by rain.
Insecticides containing bifenthrin will work, but I can make no guess about how this may affect your gelcoat or deck finish, as some insecticides will stain. A more eco-friendly solution is to spray the decks with a soap solution and let it dry. A generous squirt of detergent (3 tablespoons) to 1 gallon of water should work. Alternatively, use a mix of 1⁄2 a cup of flour and 1⁄2 a cup of milk in 1 gallon of water, sprayed liberally every five days or so, until you have got them all. The mites get caught in the mix, turning black as they desiccate and expire. sarah Brown is an environmental expert