![]() ![]() ![]() Departmental Report SCS-2000-01.The information given herein is for educational programs only. Juan Anciso, Texas AgriLife Extension Service prepared these reports August 2000 using information from numerous sources. ![]() Dudley Smith, Texas Agricultural Experiment Station and Dr. This effort is supported by the Texas Vegetable Association, and other commodity groups. For latest information regarding these issues and status of risk assessments visit ipmand Crop Briefsis an information series developed by Texas A&M AgriLife of the Texas A&M University System on critical pest problems and pesticide needs for Texas agriculture.Use is based on scouting, pest presence, and market quality expectations. Pesticides are essential to sustain production.Crop breeding continues to provide improved cultivars.Currently, carrot producers rely heavily on linuron (Lorox) for postemergence broadleaf control and sethoxydim (Poast and others ) for grass control.There are no biological control agents for weeds in carrot production. Cultural controls include fields rotations and mechanical cultivation.Problem weeds include winter annual broadleaves such as ragweed, wild parsley and london rocket plus some perennials such as bermudagrass and yellow nutsedge.There is no commerical replacement but azoxystrobin (Quadris) and propiconazole (Tilt) are being tested. Chlorothalonil (Bravo) is an FQPA targeted product that if withdrawn could negatively impact the industry by 30% in yield and quality.No biological agents control carrot diseases. Thinner spacings improve air circulation and reduce leaf spot disease. Field rotation is practiced to reduce soil-borne problems.Bacterial pathogens cause root decay in some soil conditions. Soil-borne diseases cotton root rot and Sclerotium rolfsii are favored by high soil temperatures and excessive moisture.Growers may use gibberellin to regrow new tops if Alternaria or weather severely damages foliage. Some carrot varieties are more tolerant to Alternaria than others. Major leaf spot diseases include Alternaria and powdery mildew.Currently there are no commercial replacements for diazinon for soil insects or alternatives for dichloropropene and oxamyl for nematode control. Diazinon, dichloropropene (Telone), and oxamyl (Vydate) are three FQPA targeted products that, if withdrawn, could negatively impact the industry by 25% in yield and quality losses.Biological controls are seldom used since quality is essential. All of these pests can cause crop losses up to 25% but can be controlled with insecticides/nematicides.Nematodes are more troublesome in carrots than most other vegetables. White grubs and wireworms cause root damage and quality loss.Carrot weevil mostly affects the processing carrots since food quality standards do not permit any weevil larvae presence or root damage over 1%. No carrot varieties are specifically resistant to insects.Primary production is in the Lower Rio Grande Valley the Winter Garden and High Plains also practice sequential production. Carrots are planted in August to November for staggered harvest from December to May.60% is for fresh market and 40% is for processing.9,400 acres are grown in Texas annual revenue exceeds $20 million.Juan Anisco, Texas AgriLife Extension Service Crop Brief on Production, Pests, & Pesticides Crop Briefs were prepared by Dr. ![]()
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