Campers and hikers are often warned to avoid poison oak in summer by looking out for green plants with glossy leaflets of three. However, as weather cools, the appearance of the plant changes, making it more difficult to identify.  

In fall, poison oak leaves turn attractive shades of orange and red, which then drop off in winter. The bare branches still contain allergens capable of causing a rash in sensitive individuals who brush up against it. In some cases, people may unknowingly use the plant's branches for firewood or to roast marshmallows, exposing themselves to the poisonous oils via smoke particle inhalation. 

Next time you plan a trip outdoors, make sure to read the

California ground squirrels are common throughout much of California and may be found living near homes, structures, gardens, and landscapes where they can be a real nuisance. Ground squirrels' damaging habits can include:

• Eating vegetable seedlings and green grasses
• Damaging young shrubs, vines, and trees by gnawing on and girdling trunks
• Eating twigs and leaves
• Burrowing in lawns and landscapes and around tree roots
• Gnawing on plastic sprinkler heads and irrigation lines

Effective ground squirrel management methods vary during the year. In winter, manage populations before breeding seasons begins. Visit the UC IPM publication

Dandelions are broadleaf plants easily recognizable by their bright yellow flower and puffball of white tufted seeds heads. While this plant is appreciated as a food or herb by many, for equal numbers of others it is regarded as a weed when found growing in lawns, ornamental plantings, and athletic fields throughout the year.

For helpful nonchemical and chemical management solutions to help you control this weed, read the newly revised Pest Notes: Dandelion by UC Cooperative Extension Advisor John Roncoroni.

Unlike mosquitoes, spiders do not seek people in order to bite them. Generally, a spider doesn't try to bite a person unless it has been squeezed, lain on, or similarly provoked to defend itself. Moreover, the jaws of most spiders are so small that the fangs cannot penetrate the skin of an adult person. Sometimes when a spider is disturbed in its web, it may bite instinctively because it mistakenly senses that an insect has been caught.

The severity of a spider bite depends on factors such as the kind of spider, the amount of venom injected, and the age and health of the person bitten. A spider bite might cause no reaction at all, or it might result in varying amounts of itching, redness, stiffness, swelling, and...