Fusarium wilt and the root-knot nematode are both serious diseases of cotton that cause substantial losses across the Cotton Belt. Both pathogens are common in most cotton-producing areas and often inhabit the same fields. These two pathogens often infect cotton simultaneously, forming a complex that increases the incidence and severity of Fusarium wilt.
Vol. 46, No. 2
Topics include personal digital assistants as research tools, nematode-tolerant cotton and endowed professors.
Transgenic technology has had a dramatic effect on cotton production. In 2002, more than 70 percent of Louisiana cotton acreage was planted to transgenic varieties. Cotton varieties resistant to herbicides glyphosate (Roundup Ready), bromoxynil (BXN) and glufosinate (Liberty Link) have been developed.
Despite its success throughout history, cotton as a crop in the U.S. suffers from many problems for many different reasons. Cotton in Louisiana is plagued by diseases, insect pests and dozens of competing weed species. Adverse weather in early spring is hard on this tropical plant, and rainy periods during late summer and fall often cause yield losses through boll rot and delayed harvest.
Much of the land where cotton is grown in Louisiana has been used for cotton production for decades. This has left the soil deficient in both nutrients and organic matter. Some of these deficiencies could potentially be corrected by supplementing these soils with organic waste from Louisiana’s poultry industry. This is the state’s largest animal industry generating tons of organic waste that must be disposed of in an environmentally friendly manner
Management systems that include reduced tillage and cover crops are gaining popularity. These practices typically increase plant residues at the soil surface and organic matter in the surface soil. In turn, microbial activity is increased, and the soil develops a greater capacity to adsorb and retain many types of farm chemicals, including herbicides.
LSU AgCenter scientists have launched a project to explore use of the geographical information system (GIS) and global positioning system (GPS) technologies to manage nematodes that affect cotton production in Louisiana soils.
The tarnished plant bug has always caused problems in cotton, but in recent years the problems have escalated. Data from 1990 to 1995, before the advent of transgenic Bt cotton, put the cost per acre to control the tarnished plant bug at $3.19 compared to $12.02 from 1996 to 2002, after Bt cotton was introduced.
Geospatial tools offer great promise of increasing profitability of cotton production. These tools, however, must be adapted to the specific agronomic and plant protection needs of cotton production and made available in a user-friendly format that can be easily transferred to producers, commercial pesticide applicators and agricultural consultants.
The abundance of stink bugs has increased in Mid-South and Southeastern cotton-producing states in the last six years. Stink bugs have become more common cotton pests because of a number of changes in Louisiana’s agricultural environment that have made crop and noncrop hosts available year-round.
Profitable cotton yields can be produced on Louisiana’s alluvial soils when limiting factors are overcome. These include insect, nematode and weed pests and water. Too much or too little water within the soil profile retards cotton root development and nutrient uptake efficiency. Irrigation, properly applied, can increase yields, but improper management of irrigation can limit yields.
For more than 100 years cotton has been the most important crop grown in northeast Louisiana. At one time cotton was grown all across the state, but over the years it has become concentrated in the northeast part because of more favorable environmental conditions and because other crops are preferred in south Louisiana.
Our nation’s cotton production has undergone tremendous adjustments in the past 50 years fueled by the forces of technical change. One prime indicator of the magnitude of changes is yield per acre. At the national level, per acre cotton yields have increased more than 64 percent since the mid 1950s. At the same time, area devoted to cotton production has decreased 17 percent.
Farmers have been growing cotton since 4,000 B.C. in India. In the New World, cotton production goes back well before Columbus landed in the Bahamas in 1492. He took cotton back to Spain to prove he had circled the world and reached India. Until the 18th century, England was the center of the European wool clothing industry. However, cotton soon became the preferred fiber for summer clothing.
Farming practices can affect environmental and agronomic sustainability as well as productivity. Traditional farming practices in the Mid-South typically use tillage and produce one crop each year, which exposes the soil to long periods with little or no protection from elements that cause sediment and nutrient losses.
Cotton defoliation, a critical step in cotton production, is the process of removing leaves and preparing the crop for mechanical harvest. Leaf removal facilitates harvest and allows for more efficient and faster picker operation, quicker drying of seedcotton, straightening of lodged plants, retardation of boll rot and faster opening of green bolls.
Tarnished plant bugs, which have historically been a mid-season pest of cotton, are now becoming a sporadic pest during seedling development. This is happening as agricultural conditions are changing, making it possible for more tarnished plant bugs to survive. These changes include more plant hosts because of more acres going into conservation reserve programs and an increase in conservation tillage.
Systematic research in cotton breeding and genetic improvement began in Louisiana when H.B. Brown joined the staff of the Louisiana Agricultural Experiment Station (LAES) in 1926. The objectives of the cotton improvement and breeding program were to increase lint yield, to produce more uniform, longer cotton fiber and to produce larger bolls.
Resistance monitoring provides a useful tool for detecting changes in the insecticide susceptibility of field populations of insect species from year to year.
The cotton aphid is a common secondary pest of cotton in Louisiana. Cotton aphids can infest cotton plants from seedling emergence until harvest and injure plants by continuously feeding on them. Injury symptoms may include a downward cupping of infested leaves, inter-veinal discoloration, compressed main stem nodes and reduced plant height.
Conservation tillage systems, whether no-till or stale seedbed, require use of herbicides before crop planting to rid fields of native winter vegetation and planted cover crops. Elimination of competing vegetation, which is called burndown, helps improve soil moisture and assure crop stand establishment, rapid early season growth and efficient fertilizer use.
Gene Burris (standing in striped shirt), a professor at the LSU AgCenter’s Northeast Research Station at St. Joseph, La., explains to farmers gathered for a field day about the research he is conducting to determine how to use technology to better control nematodes.