Here are two important chores to add to the fall gardening list: a thorough cleanup of the garden and monitoring for pest insect problems.
Many pest insects either lay their eggs in fall to overwinter in places that are protected from cold, wind and predators or they overwinter as adults. Several species of flies lay their eggs in fall inside fallen fruits and vegetables or in dried “mummies” left hanging on the tree or vine. Grasshoppers lay their eggs in dry, weedy patches and whiteflies and aphids lay their eggs on fallen leaves and debris and in bark crevices.
Cleaning up any possible hiding spots and disposing of all fallen or mummified summer crops in fall is key to keeping pest insect populations under control without the use of pesticides. Deciduous trees and bushes that have had aphid or whitefly infestations should be sprayed with horticultural oil after the leaves have fallen in autumn and twigs and other debris should be regularly raked up and disposed of in the green waste bin, not the compost pile.
If sycamore, elm or oak trees have shown infection by anthracnose or roses have had problems with black spot or powdery mildew, make sure to clean up all fallen leaves and debris before the winter rains arrive. These fungi can be spread by splashing water and will proliferate next spring during warm, damp weather.
Bagrada bugs are a recent invader in Southern and Central California. The stink bug has become a serious problem for home gardeners as well as commercial growers. Bagrada bugs prefer to feed on members of the mustard family including broccoli, Brussels sprout, cabbage and kale. These are winter crops in our climate. In summer, bagrada bugs feed on tomatoes, peaches, nectarines and other softer-skinned fruits and vegetables, leaving a distinctive starburst lesion where their sucking mouthpieces pierced the skin. Good photos of bagrada bugs are available on the University of California Integrated Pest Management website for help in identifying these pests.
In winter, adult bagrada bugs hide in small spaces inside outbuildings, under boards or in bark cracks. They also feed on common ornamental flowers in the mustard family – candytuft, sweet alyssum and stock. Check probable hiding places and, if you find the bugs, remove them and their food sources in the garden or protect crops with row covers.
Hoplia beetles are a spring pest problem, especially on white or light-colored flowers. The small, square, metallic-looking beetles chew holes in petals, destroying the blossoms. Hoplia beetles lay their eggs in lawns or dirt areas near their favorite food sources. In fall, the eggs metamorphose into grubs that can be killed by one or two spray applications (mixed with water) of beneficial nematodes. Beneficial nematodes are a non-toxic method of controlling many types of grubs and can be purchased online. They are living creatures that will need to be kept cool until application. When ordering try to arrange to have the package of nematodes delivered during a cool spell. Keep the package in the refrigerator until application which should take place soon after delivery.
Clovis Botanical Garden sale
The Clovis Botanical Garden will hold its annual Water-wise Plant Sale and Fair Saturday from 9 a.m until 2 p.m.. at 945 N. Clovis Ave. Admission is free. The Clovis Kiwanis Club will be selling a pancakes, eggs and bacon breakfast from 9 to 11 a.m. to give a great start your day at the garden. Breakfast is $6 per person, free for children 5 and under.
Check out the exhibitors and vendors, tour the garden in its fall glory, and bring your gardening questions to the Fresno County Master Gardeners’ booth. Clovis Botanical Garden and California Native Plant Society members receive a 10 percent discount at the plant sale; the CNPS is a co-sponsor of the event. All proceeds benefit the Clovis Botanical Garden.