How to Manage Pests

UC Pest Management Guidelines

Currently the registered preemergent materials will control only seedlings of annual and some perennial weeds. Repeat postemergent treatments are required to control perennials. With these treatments there is always some concern of injury to vines from careless application.

Primary species that are difficult to control are the perennial grasses bermudagrass, johnsongrass, and dallisgrass. The control of these weed species before planting has been discussed under the preplant section. While they are best controlled (eradicated) before planting, if after planting these weeds are still present, a program is needed for their control. All three species are sensitive to glyphosate. To achieve best control, cultivate the weeds to chop the stems and rhizomes into small pieces. Then encourage regrowth by irrigating; this will produce a lot of leaf area on the weeds. Before the weeds flower or seed, treat with glyphosate. Good coverage is important. Spot treat any regrowth if it occurs.

It will be necessary to control seedlings of these grasses with preemergent materials or spot treatments of glyphosate or paraquat before they become established. Seeds of these species last at least 2 years in the soil, so frequent monitoring is necessary for continued control. Do not allow perennial plants to reestablish and/or seed.

Two other species difficult to control are field bindweed and yellow nutsedge. Field bindweed can be reduced by irrigating in summer to encourage vigorous growth, then treating with glyphosate at flowering. This is a nonselective treatment and will kill other weeds as well. Regrowth will also have to be treated. Yellow nutsedge can be reduced in a similar manner by retreating with glyphosate before the nutsedge reaches the five-leaf stage so new nutlets do not have the opportunity to form. To be effective, it usually requires multiple applications during the season at intervals of 21 to 28 days apart. Seedling bindweed or young nutsedge can be controlled by cultivating when the soil is dry. To prevent injury to young kiwifruit vines during application of glyphosate, protect their trunks with wrappers and use a shield or hood to prevent drift onto green wood or the foliage of young vines.

PUBLICATION

UC IPM Pest Management Guidelines: Kiwifruit
UC ANR Publication 3449
Weeds
K. J. Hembree, UC Cooperative Extension, Fresno County
Acknowledgment for contributions to Weeds:
C. L. Elmore, Vegetable Crops Weed Science, UC Davis

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