Search Results

You are looking at 11 - 20 of 111 items for :

  • alternate host x
  • Refine by Access: All x
Clear All
Full access

Brent A. Holtz

Pistachio (Pistacia vera) was successfully introduced into California and initially touted as a tree nut crop with no disease or insect pests. Unfortunately, these expectations were dashed as a number of diseases and pests followed commercial plantings, making plant protection practices integral to production. Verticillium wilt (Verticillium dahliae) devastated early plantings but is now controlled with the use of resistant rootstocks. Botryosphaeria blight (Botryosphaeria dothidea) and alternaria late blight (Alternaria alternata) are recently arrived foliar fungal diseases that blight fruit clusters and defoliate trees, respectively, and multiple fungicide applications are needed for control. The conversion to low volume irrigation systems, specifically to drip or buried drip, has reduced disease. Pruning out botryosphaeria blight infections has reduced overwintering inoculum and disease, while current research aims at accurately predicting infection events to increase fungicide efficacy. A number of hemipteran insect pests have been associated with epicarp lesion: spring treatments have been replaced with dormant carbaryl and oil applications which are less toxic to beneficial insects while controlling phytocoris (Phytocoris californicus and P. relativus) and soft scale pests. Early season insect damage can be tolerated because trees compensate by maturing a higher percentage of remaining fruit kernels. Some mirid (Calocoris spp.) pests can be effectively reduced by eliminating alternate hosts in an effective weed control program. If lygus (Lygus hesperus) populations are present, weeds should not be disturbed from bloom until shell hardening to prevent movement by insects into the trees where feeding can result in epicarp lesion. Stink bugs (Pentatomidae) and leaffooted bugs (Leptoglossus clypealis and L. occidentalis) can penetrate the hardened shell and cause internal nut necrosis along with epicarp lesion. Trap crops are used to monitor pest populations in order to develop treatment thresholds. Degree-day based timing of treatments increase insecticide efficacy for the control of navel orangeworm (Amyelois transitella) and obliquebanded leafroller (Choristonuera rosaceana), but navel orangeworm populations are more effectively managed by destroying unharvested over wintering fruit. Bacillus thuriengiensis sprays, liquid-lime-sulfur, and biological control show promise in controlling obliquebanded leafroller.

Free access

Adam D. Call, Todd C. Wehner, Gerald J. Holmes, and Peter S. Ojiambo

Cucurbit downy mildew caused by the oomycete Pseudoperonospora cubensis is economically the most important disease of cucumber ( Cucumis sativus L.) ( Palti and Cohen, 1980 ). Studies on the host range of P. cubensis indicate that ≈20 genera

Free access

Jenna Sicuranza and Nathaniel A. Mitkowski

California into eastern regions of the country that have not yet tested positive for the pathogen. Because the pathogen is extremely destructive and has an extremely wide host range, it has been postulated that P. ramorum could asymptomatically infect a

Free access

E. Barclay Poling

clear whether it comes into the system from alternate hosts. Surveys are needed to determine if the pathogen occurs in the vicinity of nursery production. Sjulin (2007) reviews the more recent research of special concern to the California nursery

Full access

M. Lenny Wells, D. Scott Carlson, and R. Philip Edwards

Pecan trees, like many fruit trees, have a tendency to bear fruit in cycles, consisting of a large crop in 1 or 2 years, followed by 1 or 2 years with little or no crop. This is termed alternate bearing, and is the most profit-limiting biological

Full access

Mathews L. Paret, Ryo Kubota, Daniel M. Jenkins, and Anne M. Alvarez

, and survives on weeds and latently infected potato, geranium, and edible ginger, as well as many other hosts ( Janse et al., 2004 ; Pradhanang et al., 2000a ; Shintaku et al., 2006 ). Previous studies have shown that high populations of Rs were

Free access

Cecilia E. McGregor, Douglas W. Miano, Don R. LaBonte, Mary Hoy, Chris A. Clark, and Guilherme J.M. Rosa

controlled-release fertilizer (Osmocote 14N–6.1P–11.6K; Scotts-Sierra, Marysville, OH). Aphids and whiteflies were controlled by a weekly insecticide spray program alternating among abamectin (Avid 0.15EC; Novartis Crop Protection, Greensboro, NC), a systemic

Open access

Ebrahiem M. Babiker, Stephen J. Stringer, Barbara J. Smith, and Hamidou F. Sakhanokho

., 2010 ; Rebollar-Alviter et al., 2011 ; Zheng et al., 2017 ). T. minima is a heteroecious fungus requiring both primary and alternate host plants to complete its life cycle ( Hiratsuka 1965 ). In the northern United States, the disease cycle begins

Free access

Jason Cavatorta, George Moriarty, Mark Henning, Michael Glos, Mary Kreitinger, Henry M. Munger, and Molly Jahn

.E. Peterson's cultivar ‘Spartan Salad’ was added to ‘Marketmore 70’ by backcrossing five times alternating with two generations of self-pollination ( Jahn et al., 2002 ). The resulting cultivar was named ‘Marketmore 76’ and proved to be more widely adapted

Free access

Christian A. Wyenandt, Nancy Maxwell, and Daniel L. Ward

important for growers who have resistance on their farm to know which fungicides belong to FRAC code 11 so that these fungicides are used in tank mixes and/or in rotations with other fungicide chemistries (i.e., FRAC codes) and not used in alternation with