Using modern techniques, it has been possible to identify the earliest cotton in a copper bead within a grave in Mehrgarh. It is thought the first cotton was grown and utilised by early farmers in this region of what is now Pakistan.
Mehrgarh is home to the oldest farming settlement of Indus valley civilization. According to archaeologists, Mehrgarh was founded in year 7000 BC and abandoned in year 2500 BC. Mehrgarh predates MoenjoDaro and Harappa civilianization and, in fact, Mehrgarh was abandoned due to advent of urbanized phase of MoenjoDaro.
Extracts below explain the constant battle humans have to preserve crops under attack from pests and diseases. Genetic sequences of cotton have evidenced the makeup of cotton in the areas it is most commonly grown, ie. China, India, Pakistan, some southern states in North America.
The most damaging insects include ash weevils, have cotton aphids, cotton stem weevil, dusky cotton bug, fruit borer, leaf hopper, leaf roller, mealy bug, pink bollworm, spotted boll worm, shoot weevil, red cotton bug, stem borer, thrips, tobacco cutworm and white fly.
Diseases also attack cotton:
Cotton production is greatly affected by diseases causing yield loss and poor-quality seed and fiber. Cotton is affected by bacterial, viral, fungal, nematodal, phytoplasmal and spiroplasmal diseases (Table 6).
Cotton leaf curl disease (CLCuD) is the most devastating disease of cotton in Asia, Africa and United States. A complex of virus and DNA β-satellite molecule causes CLCuD. Nine virus species in the genus Begomovirus and DNA beta and alpha satellites are linked to cotton leaf curl disease in these regions, particularly in India and Pakistan. The first evidence of CLCuD on Gossypium hirsutum plants was reported in 1967 in the Multan district of Pakistan. It spread to all major growing areas in Pakistan and India. Due to low host resistance in existing cultivated cotton varieties, two epidemics have occurred in the past two decades. In the early 1990s, an outbreak of CLCuD devastated Pakistan’s cotton industry, causing 30% to 35% estimated yield loss. The economic loss of Pakistan in 1992 and 1997 reached ~5 billion dollars  and cotton production reduced to ~70% by 1998 in some Indian states of Punjab . A 52.7% and 54.2% decrease in boll number and cotton boll weight was observed, respectively. Yield losses were up to 50% in resistant varieties and 85% to 90% in susceptible varieties . Cotton production rebounded in the mid-1990s, when resistant cotton varieties were introduced into the Indian subcontinent . Resistance broke in 2001-2002, when new strains of CLCuV emerged that attacked previously resistant varieties, including CP-15/2, Cedex and LRA-5166 . Even China, far from CLCuD hotspots of the Indian subcontinent, reported some symptoms of this disease, raising concerns that the disease could spread far from its point of origin . Molecular biologists struggled to understand the biology of CLCuV to combat this disease .
In previous blogs, such as the Will We be Fishless series, I wrote of the continual poisoning of our global natural environment by agricultural use of pesticides, such as the infamous DDT. These are gradually being replaced by ‘genetic transformation’. Just as our Covid vaccinations often target the genetic structure of the virus attacking us, so the genetic susceptibility of varieties of cotton can be ‘transformed’ to resist both disease and insect life. We are now in an era where agriculture is improved through molecular biology research and yields are improving dramatically as a result, just as the vaccinations have saved many lives to date. So will the cotton boll weevil die out and become extinct? And where does the boll weevil sit in the food supply chain?
Wiki tells us:
The boll weevil – Anthonomus grandis, to give it its scientific name – is, like all weevils, a type of beetle. Weevils, in general, are a herbivorous beetle, and the group contains over 60,000 species, of which the boll weevil is just one. However, many other weevils do not cause significant problems for people, and so are not as well known. The boll weevil, on the other hand, can cause serious problems for us.…….It will only eat cotton plants. Since cotton is one of the world’s most important crops and was the economic lifeblood of the southern United States for a long time, it is easy to see why this tiny bug has become notorious.…………the spread of boll weevils over the last two hundred years has been dramatic. Boll weevils can now be found in Mexico, Alabama, Arizona, California, Florida, Georgia, Louisiana, Mississippi, New Mexico, North Carolina, South Carolina, Texas and Virginia…………Recently, the cost of the damage the boll weevil causes has been calculated at $300 million per year.
History records what ‘the lifeblood of the southern United States’ looked like on the cotton plantations – creating great wealth for some and misery for the slave labour.
History also tells us how pesticides used to protect cotton crops have contaminated our world and killed off precious life for the last century to the present day.
Applying pesticides reduces the numbers of other insects that would normally prey on the boll weevil and help control their numbers, such as aphids and plant bugs. So not only does the presence of boll weevils threaten the cotton plants themselves, but it can also result in a situation where the weevil’s predators cannot survive. In this way, improper pesticide applications can do more harm than good.
Boll Weevil predators:
The Fire Ant is both predator and considered a pest, so its genetics are also being studied in order to control its dominance. The Fire Ant was accidentally imported to Mobile, Alabama from a shipment arriving from Brazil, where it is commonly found. Since then it has spread widely as far as California and as far north to Maryland.
“Red imported fire ants are extremely resilient, and have adapted to contend with both flooding and drought conditions. If the ants sense increased water levels in their nests, they come together and form a ball or raft that floats, with the workers on the outside and the queen inside. Once the ball hits a tree or other stationary object, the ants swarm onto it and wait for the water levels to recede. To contend with drought conditions, their nest structure includes a network of underground foraging tunnels that extends down to the water table. Also, although they do not hibernate during the winter, colonies can survive temperatures as low as 16 °F (−9 °C).” Wikipedia
Experiments have found the Phorid Fly can destroy Fire Ants by laying its eggs in the head of the ant and then the larvae eat the ant.
But then the Phorid Fly is also considered to be a pest.
Phorid flies need anything organic to survive and meat or garbage foodstuff is more than enough to allow them to prosper. Like most small flies, Phorid flies are easy to control and you have several products to choose from. The key to success is using the right one in the right areas of the home.
The parasitic wasp Catolaccus grandis, only found in tropical areas in Mexico, is another predator of the boll weevil. They have to be introduced to the crops in the US in order to do their job of predation, but they need tropical environments to continue their existence. Genetic work is going on to create a variety which can remain in cooler temperatures.
Catolaccus grandis originated in Southeastern Mexico and it occurs naturally in the Mexican states of Veracruz, Tabasco, Campeche, Yucatan, Chiapas, Nayarit and Sinaloa (Cross and Mitchell 1969, Cate et al. 1990). This parasitoid lives in the tropical and subtropical forest and parasitizes its natural host (Anthonomus grandis) in native host plants, which include Hampea nutricia Fryxell, H. trilobata Standley, Cienfuegosia rosei Fryxel, and also in wild and cultivated cotton, Gossypium hirsutum L. (Cate et al. 1990).
Cotton trade is a massive global enterprise. When you study the countries supplying the cotton, it is clear we now live in an era where considerations are given to the ecological impact of this crop.
- The majority of the cotton comes from India, the United States and China – the world’s top three cotton producers.
- Each year, India produces an average of 5,770 thousand metric tonnes of cotton making it the world’s highest producer.
- The United States is a key producer and exporter of cotton. It produces 3,999 thousand metric tonnes a year.
- Ways to produce cotton while caring for the environment are at the forefront of conversations in the drive for sustainability.
How hard are cotton growers working to care for the environment?
Tons of water are used to irrigate cotton fields. This is a major ecological issue. As the climate warms and some cotton growing countries become more arid, the growing of cotton is threatened, but also the people may find the crop is fed water before they are.
It takes 10,000 liters of water to produce one kilogram of cotton
Global cotton production requires over 250 billion tons of water annually.
Watch how the Aral Sea diminished due to the priority of water to the cotton crop.
We love cotton. Most of us prefer it to any other fabric. But did we grow up knowing the burden growing it put on the Planet?
I did not know because I did not ask.
I am a bit late in the game to be asking such questions now, but I can find the answers because the Internet exists for all of us to search and become informed.
If pesticides are still used extensively, we all know the outcome for insects we value, such as bees. If genetic work is done, what will the long term results be for the ‘transformation’? Are we also considering not just the success of healthy crop growth, but also the impact of changing genetics of species which have evolved on this Planet for billions of years, particularly insects? And we are obviously not using precious water responsibly in growing this cash crop which means so much to the livelihoods of billions of people.
Should we consider reducing the amount of cotton we produce?
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