1.From bollworms to mealy bugs
2.Cotton insect pressure has shifted
3.Bollworm resistance to Bt cotton
4.The super-bollworm cometh
NOTE: Evidence out of China has already shown any initial reductions in pesticide use being eroded by new pest problems. The researchers warned the same patern was likely to be repeated elsewhere, and this seems to be exactly what's happening.
EXTRACTS: India - 'the mealy bug hazard being what it is, one can only hope that the proposed campaign against it is implemented meticulously. Otherwise, this menace can get out of control, nullifying the gains from the cultivation of Bt-cotton.' (item 1)
USA: 'Along with the increased use of Bt cotton came a further reduction in the use of broad spectrum insecticides. Virtual elimination of broad spectrum insecticides provided an ideal environment for stink bugs and plant bugs to flourish.' (item 2)
India: 'If the bollworm pest is seen developing resistance in the US, a country where cultivation is highly organised, land is well demarcated and farming systems are automated/ mechanised, there is no reason to believe it may not happen in India.' (item 3)
USA: 'farmers and seed companies operate according to financial incentives, and there are, in the short term, clear economic downsides to maintaining large refuges. Aside from providing prime habitat for precisely the bugs farmers hate most, they are also a pain in the ass to set up, they depress crop yields, and they reduce the amount of super-seeds companies can sell. Thus there is constant pressure on farming regulators to ease refuge requirements. ...corporate pressure on the EPA might result in the decreasing efficacy of refuge set-asides, and thus hasten the evolution of superpowered cotton-munching caterpillars.' (item 4)
1.From bollworms to mealy bugs
Surinder Sud (FARM VIEW)
Business Standard, March 11 2008
Thanks to pesticide usage falling with Bt cotton, another pest is assuming menacing proportions.
Woes of the cotton growers seem to be unending. While the threat of annihilation of their crops from the dreaded American Bollworm has abated thanks largely to the availability of pest-protected transgenic Bt-cotton hybrids, another pest is threatening to become as menacing as the bollworm. This is mealy bug, a plant sap-sucking insect having various species, some of which have multiplied to assume perilous proportions chiefly because of the reduction of pesticide use after the spread of Bt-cotton.
A significant presence of these white-coated insects, viewed earlier as merely minor pests, was observed on the cotton crop in Gujarat in 2006 and, subsequently, in Punjab and the adjoining northern cotton-growing tracts in 2007. There have been reports of its growing populations from most other cotton-growing states as well. In 2005, the mealy bugs had destroyed almost the entire cotton crop in several parts of Pakistan, notably in Multan, Sanghar, Mirpurkhas and Tandu Allahyar areas.
What is worse, entomologists feel that if preventive action is not initiated immediately, the pest may cause extensive damage to the next cotton crop to be planted from April onwards. For, a good deal of pest load already exists in the cotton belts. Apart from cotton, this pest can also pose hazards for other commercial crops, including grapes and jute and mesta, where it can lead to 50 to 100 per cent yield loss.
Fortunately, the agriculture ministry has taken the forewarning by the scientists of the Indian Council of Agricultural Research (ICAR) with the seriousness it merits. It has, consequently, prepared a programme for creating awareness of the mealy bug menace and to educate farmers on the ways of combating it. The scheme, costing Rs 130 lakh, will be implemented from the coming kharif season itself.
According to O M Bambawale, director of the New Delhi-based National Centre for Integrated Pest Management, the widespread cultivation of Bt-cotton, which had resulted in substantial yield gains, had also led to a change in the overall pest scenario. Instead of bollworms, several other pests were threatening the crop now. These include parawilt, grey mildew, mirid bugs, mealy bug, thrips and the like.
The mealy bug insect, indeed, is different from most other pests in several respects which pose special problems in combating it. The most significant ”” as also, perhaps, odd ”” among them is that males are not necessary for reproduction in mealy bugs. Female adults lay, on their own, around 400 to 600 eggs which are capable of growing into young mealy bugs called crawlers, because of the way they move about, within three to nine days.
Besides, on maturity, these insects acquire a cottony look because of their soft bodies that get covered with white mealy wax, making them virtually indistinguishable from cotton. Moreover, when the cotton plants are not in the fields, these pests can survive, and even thrive, on several other plant species as also on the cotton sticks and other parts of the plants which are generally kept by the farmers for use as fuel. These pests, because of their sticky nature, can travel to distant places by clinging on to farm equipment, animals or even people and agricultural workers moving from one place to another.
Indeed, both young ones and adults are enemies of the plants. By sucking the sap from leaves, they cause withering of leaves, stunting of plant growth, and premature dropping-off of cotton bolls. In the case of heavy infestation, the pest can totally denude the plants of leaves, leading to their demise.
Worse still, no mealy bug-resistant cotton varieties or hybrids are available as yet. Pesticides need to be sprayed five to six times to control the pest. These cost over Rs 3,500 a hectare, which many farmers can ill-afford. Experts are, therefore, advising growers to take preventive measures to ward off this menace.
For this, the farmers need to eradicate the alternative host plants, notably weeds like the Congress grass (parthenium). They are also required to destroy the colonies of ants during the land preparation operations as the ants help and abet in the survival of the pest. However, once the crop is in the field, constant monitoring is essential for early detection and destruction of the pests.
Indeed, the mealy bug hazard being what it is, one can only hope that the proposed campaign against it is implemented meticulously. Otherwise, this menace can get out of control, nullifying the gains from the cultivation of Bt-cotton.
2.Cotton insect pressure has shifted
By Roy Roberson
Farm Press, Mar 10 2008 [extracts]
Stink bugs in the Southeast and plant bugs in the Mid-South have created problems for cotton growers who once thought these little critters were gone for good.
In the Southeast the major problem is with stink bugs, though other plant bugs are sporadic pests of cotton. In the Mid-South, plant bugs, including lygus, tarnished plant bugs and cotton fleahoppers are the primary problems, with little pressure from stink bugs.
Since 1996 the use of Bt-containing cotton varieties has steadily increased. Along with the increased use of Bt cotton came a further reduction in the use of broad spectrum insecticides.
Virtual elimination of broad spectrum insecticides provided an ideal environment for stink bugs and plant bugs to flourish. In general, states where boll weevil eradication was the most successful early in the program, now have the heaviest pressure from plant and stink bugs. Georgia, for example, was declared boll weevil free in the early 1990s, and growers there have seen a steady increase in stink bug pressure.
In addition, a number of specialized insecticides to help control tobacco budworm have been widely used. These so called soft chemistries have little impact on plant bugs and stink bugs.
Then in 2003 and 2005 Bollgard II and WideStrike came to the market place, further reducing the use of broad spectrum insecticides.
In general plant bugs are a problem in the Mid-South and stink bugs are a problem in the Southeast. However, entomologists warn that as more areas are declared boll weevil free and as the use of Bt cotton continues to grow, there is a threat that this could flip-flop.
3.Bollworm may be developing resistance to Bt cotton
Research reports from US say pests are in the process of turning immune
G. Chandrashekhar The Hindu Business Line, Feb 21 2008 http://www.thehindubusinessline.com/2008/02/21/stories/2008022150991300.htm
Mumbai, Feb. 20 Even as life science companies in seed business and vocal lobbyists for pro-genetically modified (GM) crops combine to make propagandist noises about the goodness of the technology and rapid spread of area under GM crops worldwide comes the news that pests are slowly developing resistance to transgenic crops.
Currently, corn (maize), soyabean and cotton are the major field crops in which transgenic varieties have been commercialised. Cotton was the first major field GM crop to go commercial in 1996 in the US. Incidentally, the US is the world's largest producer of soyabean and corn.
Gene from a bacterium - Bacillus thuringiensis (Bt) - is inserted in the cottonseed as a result of which the plant repels bollworm attack by secreting a protein-based toxin that kills the insect and saves the plant.
The latest is that reports, based on extensive research, emanating from the US suggest that pests may be in the process of evolving resistance to modified crops. A study of the Bt Cotton crop by researchers in the US has revealed that the bollworm which is widely known to attack cotton boll and inflict losses were slowly developing immunity.
Reports in the western press suggest the University of Arizona found resistant form of bollworm caterpillar in a dozen fields in the southern states of Mississippi and Arkansas between 2003 and 2006. Until last year, the US was the world's second largest cotton producer. It continues to be a major exporter with over 70 per cent of output destined for overseas markets.
However, area under cotton has begun to shrink following competition for acreage from crops such as corn, soyabean and wheat.
Coming about 7-8 years after commercialisation of Bt. Cotton, the survey findings of evolving resistance are sure to not only cause concern, but also set alarm bells ringing in major cotton growing countries that have embraced the technology.
In India, GM-cotton was commercialised in 2002. Since then, cotton output has surged by leaps and bounds year after year; and in 2007 it stood at over 300 lakh bales. Over 50 per cent of the country's acreage under cotton (90 lakh hectares) is accounted for GM seeds.
The technology has delivered, so far. It is possible some kind of fatigue could be setting in? If the bollworm pest is seen developing resistance in the US, a country where cultivation is highly organised, land is well demarcated and farming systems are automated/ mechanised, there is no reason to believe it may not happen in India.
Indeed, it would be almost impossible to isolate area and control the pest in our country given the nature of agriculture - fragmented lands and millions of growers.
It is necessary for the Government, the scientists and the industry to work together to initiate studies to ascertain the status of pest resistance in our country. When we embrace technologies from abroad, we can ill-afford to overlook related developments there.
India is today the world's second largest producer of cotton and a very large exporter. It has emerged as a force to reckon with in the global cotton sector.
Indian cotton growers are small. Crops lost to pests that have developed resistance can have devastating effect on our rural economy. The way forward is to closely monitor the situation and initiate remedial measures.
4.The super-bollworm cometh
The Salon, 7 March 2008
Mutating bugs that resist transgenic toxins! It's the kind of news that makes Greenpeace activists shout 'I told you so' and gives Monsanto scientists sleepless nights: Entomologists at the University of Arizona have documented 'the first case of field-evolved resistance to a Bt toxin produced by a transgenic crop.'
The insect is Helicoverpa zea, aka: the bollworm. The crop is Bt cotton, better known by the Monsanto brand name Bollgard. The Bt toxin is Cry1Ac -- death to all lepidopteran insects.
The researchers, led by Bruce Tabashnik, chair of the UA entomology department, published their disconcerting news in the February issue of Nature Biotechnology. A good summary can be found here. But before we all go running into the streets, shrieking and rending our garments at the emergence of this long-awaited and long-feared genetically modified-induced insect mutation sure to ruin all of global agriculture, there are some mitigating circumstances to consider..
According to Tabashnik, the superbugs took longer than predicted by entomological computer modeling to arrive. The researchers evaluated large datasets of information focusing on six cotton pests in Australia, China, Spain and multiple locations within the U.S., but Cry1Ac-resistance was found only in bollworms in Arkansas and Mississippi. Newer versions of transgenic cotton include a second generation Bt toxin, Cry2Ab, for which the bollworm has as yet evolved no defense. Finally, the available evidence appears to validate the 'refuge' strategy of transgenic crop pest management, in which farmers are required to plant non-Bt crops in fields adjoining Bt crops in order to provide a hospitable environment for non-resistant pests to thrive. In regions where greater acreage has been devoted to refuges, the development of Cry1Ac resistance seems to have been delayed.
The purpose of the 'refuge' strategy is to prevent toxin-resistant bugs from hooking up with other toxin-resistant bugs and making lots of toxin-resistant babies. Resistant bugs are expected to be relatively rare, so if acreage is set apart for non-resistant bugs to breed that's where the bad bugs will find their mates. If the gene for resistance is recessive, which it tends to be with cotton-eating caterpillars, the hybrid babies won't express the resistant trait.
If this seems like a somewhat sloppy, hit or miss approach, well, welcome to farming. Entomologists can cite reams of computer data in support of models that recommend exactly how much acreage should be planted with non-Bt crops or what ratio of non-resistant to resistant insects is ideal for the prevention of resistance development (500-1 is considered just right). But there's no silver bullet. To provide just one example of the imponderables at work: the resistance to Cry1Ac trait in cotton pests is not always recessive. In the case of H. zea the trait appears to be statistically more dominant than in other cotton pests, which might explain why H. zea was the only one of six different lepidoptera to develop resistance, so far.
Therefore, in regions where H. zea is prevalent, entomologists might argue for a greater percentage of acreage to be set aside as a refuge, with the goal of further diluting the breeding potency of resistant bugs.
The long-term goal is not to prevent resistance from ever developing. That's not how nature works. Eventually insects will evolve resistance to any toxin, natural or human-made. The goal is to delay resistance from developing long enough so that it becomes manageable, so that, perhaps, by the time super-bollworms evolve, there are new versions of super-Bollgard available to farmers to contain the threat.
In a perfect world in which scientists impartially evaluated data and designed rigorous management strategies which farmers and seed companies than scrupulously cooperated to execute, it's possible that the showdown between anti-GM activists and biotech companies might be a little less ideologically fraught and vituperative. But of course, farmers and seed companies operate according to financial incentives, and there are, in the short term, clear economic downsides to maintaining large refuges. Aside from providing prime habitat for precisely the bugs farmers hate most, they are also a pain in the ass to set up, they depress crop yields, and they reduce the amount of super-seeds companies can sell. Thus there is constant pressure on farming regulators to ease refuge requirements.
An excellent history of how the Environmental Protection Agency developed its refuge models, published late last year in the Southwest Farm Press, concludes with one scientist noting that the final decision on how to handle refuges was up to the EPA, 'which is responsible to all those stakeholders.'
But as any one who has been paying attention to the Bush administration is all too aware, some stakeholders are more equal than others. Some stakeholders end up completely coopting their regulators, and enjoy the privilege of designing their own regulations.
When the debate between anti-GM activists and Monsanto apologists becomes a shouting match in which supposedly omniscient scientists are matched up against Nature-worshipping greens, How the World Works starts to lose interest. In that kind of polarization all nuance gets lost. But when the debate is whether corporate pressure on the EPA might result in the decreasing efficacy of refuge set-asides, and thus hasten the evolution of superpowered cotton-munching caterpillars, that's where we start to get fascinated.