ISIS Report 01/02/10

GM Crops Facing Meltdown in the USA

ISIS報告：轉基因農作物在美國面臨崩潰

翻譯：Silence 校對：義成

文章來源：http://www.i-sis.org.uk/GMCropsFacingMeltdown.php

在轉基因生物的中心地帶，經遺傳改造而具有耐受除草劑和抗蟲性兩類顯著特性的主要農作物，正在被超級雜草和次生害蟲破壞，農民也在為更多同樣的敗局而抗爭；向有機耕作實踐的根本性轉變也許是唯一挽救之道。——侯美婉博士

請廣泛傳播，保持所有的鏈接不變，并交給貴國政府代表要求停止轉基因農作物的種植，要求支持非轉基因的有機農業！

兩種顯著特性涵蓋了目前世界上商業化種植的所有的轉基因（GM）農作物：耐受除草劑（HT）特性，因含有從一類土壤細菌－－根癌農桿菌（Agrobacterium tumefaciens）獲得的5 -烯醇丙酮莽草酸3-磷酸合成酶（EPSPS）編碼基因而對草甘膦除草劑不敏感；抗蟲特性，由于含有一個或更多的從另一類土壤細菌－－蘇云金芽孢桿菌(Bacillus thuringiensis)獲得的毒素基因。在美國－－轉基因生物的中心地帶，商業化種植轉基因作物開始于1997年左右，並在此后的許多年間迅速增加。截至目前，在美國三大主要農作物——大豆、玉米和棉花的耕種區域[1]（見表1），轉基因作物已達85%-91%，其種植面積近171百萬英畝。

伴隨轉基因農作物的生態定時炸彈已經漸行漸近，它即將被引爆。

耐受除草劑的農作物助長了除草劑的使用，導致抗除草劑雜草的產生，反過來又需要更多的除草劑。但越來越多的使用劇毒除草劑和除草劑混合物，沒能阻止在耐受除草劑的農作物田中超級雜草的繼續生長。同時，次生害蟲如抗Bt毒素的牧草盲蝽，成為破壞美國棉花的最主要害蟲。

殺不死的植物怪物

現在是“三腳樹”的時代——這種三腳樹不是指約翰·溫德姆的科幻小說《三腳樹時代》中提到的轉基因植物，而是“殺不死的超級雜草”[2]。正如美國廣播公司電視新聞曾報道，這種超級雜草是由于種植抗除草劑的轉基因作物而被創造出來的。

電視新聞的現場是2009年10月阿肯色州的收獲季節。表情嚴峻的農民和科學家正在布滿巨藜的田間交談，這種巨藜即使噴灑再多的草甘膦除草劑都死不了。一位農民在3個月內花了50萬美元試圖清除怪物雜草，仍然徒勞；聯合收割機和手工工具對這些雜草都無能為力。據估計，在阿肯色州有100萬英畝的大豆和棉花田中已大量滋生怪物雜草。

ABC新聞報道：超級雜草

長芒莧或藜是最可怕的雜草。它可長至7-8英尺高，耐高溫和長期干旱，產生數千種子，并有可從農作物吸盡養分的發達根系。如果任其發展，在一年內將占領整個農田。

與此同時，在北卡羅萊納州珀奎曼斯縣，農民兼農業推廣人員保羅·史密斯剛剛在他的田里發現可惡的雜草[3]，他也將不得不雇用移民隊以手工除草。

預計這種抗除草劑雜草會侵入鄰近的縣。它早已產生針對至少三種其他類型除草劑的抗性。

抗除草劑的雜草并不是新鮮事。在北卡羅萊納州有10種，全國有189種雜草對一些除草劑產生抗性。

北卡羅萊納州立大學的退休農學教授、國家級雜草專家艾倫·約克說，“不太可能生產一種新型除草劑。”

抗草甘膦雜草的產生是由于廣泛種植抗除草劑農作物

草甘膦是美國和世界上最廣泛使用的除草劑。自20世紀70年代以來，它被孟山都公司以農達為商標名稱和專利配方申請專利權并銷售。隨著抗除草劑農作物的種植而流行使用。美國農業部的數據表明，在主要農作物上的草甘膦的使用量在1994年至2005年間增長了15倍多[4]。據EPA（美國環保署）估計，在2000-2001年，每年1億磅草甘膦用于草地和農場 [5]，在過去的13年里，它已應用于超過10億英畝的農田里[6]。

抗草甘膦的雜草不久就出現了，就像很多雜草對以前使用的每一種除草劑產生了抗藥性的情形一樣。美國雜草科學學會公布在美國有9種雜草被確認抗草甘膦[6]；其中有普通豚草(Ambrosia artemisiifolia)，普通waterhemp（莧菜藤子）(Amaranthus rudis)，巨豚草（三裂葉豚草）(Ambrosia trifida)，毛燈盞細辛(Conyza bonariensis)，加拿大乍蓬(Conyza canadensis)，意大利黑麥草(Lolium multiflorum)，假高粱 (Sorghum halepense)，剛性黑麥草(Lolium rigidum)和帕默藜(Amaranthus palmeri)。

抗草甘膦超級雜草

在2004年年底，抗草甘膦的帕默藜首次出現在佐治亞州梅肯縣，并已蔓延到佐治亞州其他地區以及南卡羅來納州、北卡羅來納州、阿肯色州、田納西州、肯塔基州和密蘇里州[7]。根據佐治亞大學雜草專家斯坦利·卡爾佩珀估計，佐治亞州有10萬英畝農田嚴重布滿了藜，有29個縣現已證實藜是抗草甘膦的。 2007年，在梅肯縣，1萬英畝農田因抗草甘膦藜大量滋生而被拋荒。

據報道，孟山度公司技術開發部經理里克·科爾曾說，這樣的問題是“可管理的”。他建議農民輪種并使用不同品牌的除草劑。孟山都的銷售代表正在鼓勵農民把草甘膦和以前使用的除草劑如2，4-二氯苯氧乙酸 （2,4-D）混合使用。2,4-二氯苯氧乙酸在瑞典、丹麥和挪威三個國家因與癌癥、生殖和神經系統的損害有關而被禁用，它是1960年代在越南使用的橙劑的組分之一。

據報道佐治亞州的農民已改種傳統的非轉基因作物。

佐治亞大學的雜草科學家估計，每6米棉行中的平均僅兩種長芒莧雜草會使棉花產量減少百分之二十三[8]。一棵雜草可以產生450000粒種子。在阿肯色州、田納西州、新墨西哥州、密西西比州以及最近的亞拉巴馬州，農田已經布滿雜草。

百草枯被推薦在保護性耕作方案中使用，與其他三種除草劑混合使用。每一種除草劑以不同的作用模式除草。田納西大學的科學家們已經發現帕默雜草不僅抗草甘膦而且抗磺酰脲類除草劑三氟啶磺酸鈉。

草甘膦抗性極易產生

早在耐受除草劑的轉基因作物被引入之前，批評人士已經預測，抗草甘膦雜草只需通過抗除草劑作物和其同屬的野生雜草之間交叉授粉就繁殖出來了。但他們忽視了“流動基因組”機制，這些機制在應對環境刺激時可改變基因組和基因，並使大多數雜草產生針對除草劑的抗性而不依賴于交叉授粉。在我的書－－《遺傳工程：美夢還是噩夢》（1997/1998年第一版）的“偽科學和大企業的冒險新世界”這章節中，我就注意到這些機制 [9]

美國科林斯堡的科羅拉多州立大學的一個由托德·蓋恩斯領導的研究小組調查了來自佐治亞州的抗草甘膦藜種群。他們發現，與對草甘膦敏感的植物相比，抗性植物體內負責代謝草甘膦的EPSPS這種酶的編碼基因擴增（增殖）了5至160倍 [10]。該基因的表達水平與基因的拷貝數呈正相關。針對該基因的熒光染色表明，被擴增的基因副本存在于每一條染色體。

至少自20世紀80年代以來就已經知道，基因擴增是細胞和生物體對環境中的“選擇的”因子最常見的生理反應之一 [9]。

到2009年，有16種雜草被確認有草甘膦抗性[10]。目前已確定的抗性機制包括：草甘膦吸收率降低，和/或EPSPS基因發生突變而使得雜草更難以被除草劑抑制。抗草甘膦藜是首個基于基因擴增而產生抗性的案例。這個例子證明對不受歡迎的因子產生抗性可輕易地進化出來，也證明對大自然發起 “化學戰”是徒勞的。

牧草盲蝽：最有害的棉花蟲害

在2008年，“牧草盲蝽”侵染了美國480萬英畝棉田[11]，成為最具破壞性的棉花害蟲。另外一種害蟲，棉盲蝽象名列第五，侵害面積達230萬英畝。

從加州圣華金河谷流域到弗吉尼亞州東南部的美國的棉花種植帶，現在65%的區域都種植了Bt轉基因棉花(Table 1 [1])，棉籽象鼻蟲和煙草蚜蟲自從Bt棉花引種以來已經很罕見了。但是在印度及其他地方[12, 13]，次生害蟲特別是牧草盲蝽造成了嚴重危害。

牧草盲蝽（TPB），學名Lygus lineolaris,從有記錄可查的歷史以來一直是棉花害蟲。在1995年以前，它被針對其他害蟲（如煙草蚜蟲和棉籽象鼻蟲）的殺蟲劑控制住。根據密西西比州立大學三角洲研究與推廣中心的研究人員的研究[14]，自廣泛種植Bt轉基因棉花與撲滅棉籽象鼻蟲以來，殺蟲劑用量減少；結果牧草盲蝽成為棉田的主要蟲害。

 “額外的昆蟲控制成本源自增加葉面噴灑、較高的技術費和害蟲抗性。”三角洲研究與推廣中心昆蟲研究學者杰夫·戈爾在2010年新奧爾良陸地棉種植會議上介紹說。[15]

在1995年種植一英畝棉花成本為12.75至24美元；在2005年，種植一英畝用“卡迪拉克”處理過種子的抗蟲保鈴棉、抗農達除草劑棉花的成本是52美元。現在2010年，種植一英畝（孟山都公司的）第二代抗蟲保鈴棉和抗農達除草劑棉，農民們要花費85美元或更多。

 “在密西西比州，有的棉農要花費超過100美元來控制葉面蟲害。你把技術費和種子處理費用加上，就會明白為什么我們的棉花種植面積正在減少。”戈爾說。

更嚴重的問題是，牧草盲蝽已經對幾類殺蟲劑產生抗性，尤其是在中南部州的三角洲地區 [14]。

雖然牧草盲蝽是棉花整個生長周期的害蟲，但在開花期蟲害特別嚴重，此時害蟲大量繁殖，所以其成蟲和幼蟲都會吸食棉花。大多數蟲害吸食發生在棉花的生殖組織。害蟲把它們的口器插入小的棉鈴。在三角洲的一些地區因缺乏有效控制，由牧草盲蝽造成農作物幾乎全部損失并非罕見。

中南部的棉農向戈爾請教種植非轉Bt基因的棉花品種，尤其是那些因Bt生物技術花費更高成本的棉農[15]。“我們有一些種植者種了小面積的非轉Bt基因的棉花，它們大概從中看到了利潤。”

 “但如果我們開始重新種植非轉Bt基因棉花，我向你保證，煙草蚜蟲就會回來，我們在對付牧草盲蝽之外，不想為了殺死煙草蚜蟲而又葉片噴施殺蟲劑。在那種情況下，我們被迫的支出的金額將是無法估量的。”

牧草盲蝽在過去四至五年已成為中南部的第1號害蟲，正在驅使不再能夠負擔得起噴劑的費用的許多棉農離開密西西比三角洲流域。

戈爾透露，在南方，葉螨連同蚜蟲、椿象一起，也正在獲得“預算破壞者”這樣的名聲。

像牧草盲蝽一樣，葉螨對用來控制它們的殺蟲劑正在產生抗性。 “過去15年以來，我們已經基本上翻倍了百治磷（Bidrin）的使用率，乙酰甲胺磷的使用率則增至三倍。因此，我們不僅正在噴灑更多的殺蟲劑，我們也正以更高的使用率而使成本也提高了很多。”戈爾說。

他指出，為了防治植物蟲害而對新煙堿類殺蟲劑依賴的副作用是在棉花蚜蟲中已經產生了一些抗藥性。 “我們開始聽到來自中南部許多咨詢者的抱怨。”

更多的類似做法是徒勞的

預測令人失望，給農民的唯一的官方學術建議是會首先產生問題的更多的相同的常規做法，即噴灑更多或噴灑不同種類殺蟲農藥的混合劑，包括已被禁止使用的太毒的殺蟲劑。同時，工業已經做好準備以出售含多種轉基因性狀的品種，可多達八個性狀但加倍了種子價格 [16]。

令人失望的是一些國家政府和政府的科學家堅持不懈的努力去促進失敗的轉基因技術，而我早就講清楚，那些技術自20世紀80年代初以來已經過時[9]。一份Sciencexpress文件（顯示快速出版物，大概沒有經過同行評審）題為“糧食安全：喂養90億人的挑戰”[17]其中英國首席科學家約翰·貝丁頓教授為合著者，盡管其中有些輕視目前的轉基因作物，但他們仍堅持我們超過30年聽到的承諾。 “未來十年，將看到的理想特性組合的發展和新的特性如抗旱性的引入。到本世紀中葉涉及多基因性狀的更為激進的方案可能是切實可行的。”它繼續承諾“克隆具有對疾病先天免疫進行遺傳的動物”等。

草甘膦和“農達”，仍然在把可耐受除草劑的農作物當作“雜草戰士”推廣的生物技術研究所小冊子中被標榜成“對我們的毒性比餐桌上的食鹽還低”[18]，實際上正如新的研究結果顯示它們非常毒[19，20]（多毒導致死亡，草甘膦和農達，SIS42；現在禁止草甘膦除草劑，SIS43）。 在美國13年的轉基因作物種植整體上增加了318百萬英磅的殺蟲劑用量[21]（在美國轉基因作物增加了除草劑農藥的使用量，SIS45）。單從這一因素導致的該國額外的疾病負擔相當可觀。

印度已嘗到了來自轉基因Bt棉花教訓[22]的苦果 ，在惡化的農場自殺事件中，以及同美國一樣，在由次生的與新的棉花害蟲、抗BT害蟲、新疾病帶來的生態災難中，最重要的是，土壤耗盡了營養物質和有益微生物而在10年內將不再支持任何農作物的生長。他們的唯一救星是回歸有機農業，因為它已經證明比Bt棉更可持續、利潤更高[12]。這可能也會應用于美國。

現在需要耕作實踐的一個根本性的轉變

在美國，盡管經濟衰退，有機產品市場增長勢頭強勁。據來自美國農業部的最新報告，有機食品的零售銷售從1997年的36億美元上升到2008年度的 211億美元 [23]（見圖1）。該市場是如此活躍，以至于有機農場有時要勉力去生產出足夠的供應以滿足迅速增長的消費需求，從而導致有機產品的周期性短缺。

 圖1 從1997年到2008年美國有機市場的增長態勢

經認證的有機耕地面積從1997年時的130萬英畝至2005年的400多萬英畝（占美國所有農業土地的百分之0.5），已增加了一倍多。在同一時期，有機農場數目從5 021增至8 493，經認證的有機農場的平均規模從268英畝增至477畝。

那么，為什么美國農民沒能利用迅速擴大的市場優勢？有人認為[23]，潛在的有機農民可能選擇繼續常規的生產方法，因為“來自附近的對有機農業持有負面看法的其他農民的社會壓力”，或因為在過渡期內無法應對天氣導致的產量和利潤減少的影響。這并不奇怪，由于GM支持者包括政府監管機構對有機農業進行的持續的負面宣傳的緣故。（例見由英國食品標準局最近試圖證明有機食品的營養不超過常規食品，但它與以下報道相背逆[24]（英國食品標準局的研究證明有機食品更好，SiS44）。通常的聲稱是，有機農業比常規農業產量較少和需要更多能量，且有機農產品沒有更多營養或健康，但與常規生產方式相比卻不衛生。在帶有已公布科學文獻的證據的ISIS報告－－現在看糧食的未來：*有機* 可持續*不使用化石燃料[25]以及其他研究中，這些虛假聲稱已被徹底駁斥 。

與美國農民最相關的一個研究是由愛荷華州立大學的凱瑟琳·戴拉特和美國農業部的Cynthia A.Cambardella所作的關于從常規農業轉變為經認證的有機生產的三年過渡期中的農場績效評估[26] 。持續四年（三年過渡期的和第一年有機）的實驗顯示，對大豆和玉米來說，雖然初期產量下降，但在第三年扳平，在第四年有機產量都超出常規農業。

我們的報告[25]也證明（有機耕種）減少溫室氣體排放量的巨大潛力 - 甚至可使我們完全擺脫對化石燃料依賴的程度——通過有機農業和當地化食品（和可再生能源）系統。這是最新的科學分析與由農民領銜研究的案例的獨特結合，尤其是農民自己的經驗和創新，往往挫敗了拘泥于陳舊和過時理論的學術科學家，其中，轉基因技術是一個突出的例子。

大約在我們的報告公布后的同一時間，國際農業知識、科學和技術的發展評估（IAASTD）也出版了。 IAASTD是400名參與科學家和來自全球110個國家的非政府代表三年深思熟慮的成果[27]。它得出的結論是，小規模的有機農業是戰勝饑餓、社會不平等和環境災害的前進途徑[28]（“無轉基因的有機農業養活世界”，SIS38）。

在農業的崩潰完成之前，現在需要耕作實踐中的一個根本性的轉變。

原文：

ISIS Report 01/02/10

GM Crops Facing Meltdown in the USA

Major crops genetically modified for just two traits - herbicide tolerance and insect resistance are ravaged by super weeds and secondary pests in the heartland of GMOs as farmers fight a losing battle with more of the same; a fundamental shift to organic farming practices may be the only salvation Dr. Mae-Wan Ho

Please circulate widely, keeping all links unchanged, and submit to your government representatives demanding an end to GM crops and support for non-GM organic agriculture

Two traits account for practically all the genetically modified (GM) crops grown in the world today: herbicide-tolerance (HT) due to glyphosate-insensitive form of the gene coding for the enzyme targeted by the herbicide, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), derived from soil bacterium Agrobacterium tumefaciens, and insect-resistance due to one or more toxin genes derived from the soil bacterium Bt (Bacillus thuringiensis). Commercial planting began around 1997 in the United States, the heartland of GM crops, and increased rapidly over the years. By now, GM crops have taken over 85-91 percent of the area planted with the three major crops, soybean, corn and cotton in the US [1]] (see Table 1), which occupy nearly 171 million acres.

The ecological time-bomb that came with the GM crops has been ticking away, and is about to explode.

HT crops encouraged the use of herbicides, resulting in herbicide-resistant weeds that demand yet more herbicides. But the increasing use of deadly herbicide and herbicide mixtures has failed to stall the advance of the palmer super weed in HT crops. At the same time, secondary pests such as the tarnished plant bug, against which Bt toxin is powerless, became the single most damaging insect for US cotton.

Monster plants that can’t be killed

It is the Day of the Triffids - not the genetically modified plants themselves as alluded to in John Wyndham’s novel - but “super weeds that can’t be killed” [2], created by the planting of genetically modified HT crops, as seen on ABC TV news.

The scene is set at harvest time in Arkansas October 2009. Grim-faced farmers and scientists speak from fields infested with giant pigweed plants that can withstand as much glyphosate herbicide as you can afford to douse on them. One farmer spent US$0.5 million in three months trying to clear the monster weeds in vain; they stop combine harvesters and break hand tools. Already, an estimated one million acres of soybean and cotton crops in Arkansas have become infested.

The palmer amaranth or palmer pigweed is the most dreaded weed. It can grow 7-8 feet tall, withstand withering heat and prolonged droughts, produce thousands of seeds and has a root system that drains nutrients away from crops. If left unchecked, it would take over a field in a year.

Meanwhile in North Carolina Perquimans County, farmer and extension worker Paul Smith has just found the offending weed in his field [3], and he too, will have to hire a migrant crew to remove the weed by hand.

The resistant weed is expected to move into neighbouring counties. It has already developed resistance to at least three other types of herbicides.

Herbicide-resistance in weeds is nothing new. Ten weed species in North Carolina and 189 weed species nationally have developed resistance to some herbicide.

A new herbicide is unlikely to come out, said Alan York, retired professor of agriculture from North Carolina State University and national weed expert

Glyphosate-resistant weeds from widespread planting of HT crops

Glyphosate is the most widely used herbicide in the US and the world at large. It was patented and sold by Monsanto since the 1970s under the trade name and proprietary formulation, Roundup. Its popularity shot up with the introduction of HT crops. Data from the US Department of Agriculture indicate that the use of glyphosate on major crops went up by more than 15 fold between 1994 and 2005 [4]. The EPA estimated in 2000-2001 that 100 million pounds of glyphosate are used on lawns and farms every year [5], and over the last 13 years, it has been applied to more than a billion acres [6].

It did not take long for glyphosate-resistant weeds to appear, just as weeds resistant to every herbicide used in the past had appeared. The Weed Science Society of America reported nine weed species in the United States with confirmed resistance to glyphosate [6]; among them are strains of common ragweed (Ambrosia artemisiifolia), common waterhemp (Amaranthus rudis), giant ragweed (Ambrosia trifida), hairy fleabane (Conyza bonariensis), horseweed (Conyza canadensis), Italian ryegrass (Lolium multiflorum), johnsongrass (Sorghum halepense), rigid ryegrass (Lolium rigidum), and palmer pigweed (Amaranthus palmeri).

Glyphosate-resistant palmer super weed

Glyphosate-resistant palmer pigweed first turned up in late 2004 in Macon County, Georgia, and has since spread to other parts of Georgia as well as to South Carolina, North Carolina, Arkansas, Tennessee, Kentucky and Missouri [7]. An estimated 100 000 acres in Georgia are severely infested with pigweed and 29 counties have now confirmed pigweed resistance to glyhosate, according to weed specialist Stanley Culpepper at the University of Georgia. In 2007, 10 000 acres of glyphosate-resistant pigweed infested land were abandoned in Macon County.

Monsanto’s technical development manager Rick Cole was reported saying that the problems were “manageable”. He advised farmers to alternate crops and use different makes of herbicides. Monsanto sales representatives are encouraging farmers to mix glyphosate and older herbicides such as 2,4-D, banned in Sweden, Denmark and Norway on account of links to cancer and reproductive and neurological damages. It is a component of Agent Orange used in Vietnam in the 1960s.

Farmers in Georgia are reported to be going back to conventional non-GM crops.

Weed scientists at the University of Georgia estimate that an average of just two palmer amaranth plants in every 6 m length of cotton row can reduce yield by at least 23 percent [8]. A single weed plant can produce 450 000 seeds. Many fields in Arkansas, Tennessee, New Mexico, Mississippi and most recently, Alabama are also infested.

Paraquat is recommended for use in conservation tillage programmes, mixed with up to three other herbicides, each with a different mode of action. Scientists at the University of Tennessee have seen palmer weeds resistant not only to glyphosate but also to the sulfonylurea herbicide trifloxysulfuron-sodium

Glyphosate resistance with the greatest of ease

Critics have been predicting glyphosate-resistant weeds before HT crops were introduced, simply through cross-pollination between HT crops and wild weedy relatives. But they had neglected the ‘fluid genome’ mechanisms that can alter genomes and genes in response to environmental stimuli, enabling most weed plants to become herbicide resistant independently of cross-pollination. I drew attention to these mechanisms in my book Genetic Engineering Dream or Nightmare, the Brave New World of Bad Science and Big Business [9] first published in 1997/1998.

Researchers led by Todd Gaines at Colorado State University, Fort Collins in the United States investigated glyphosate-resistant palmer pigweed populations from Georgia. They found that the gene coding for the enzyme EPSPS responsible for metabolising glyphosate herbicide was amplified (multiplied) 5 to 160-fold in glyphosate-resistant plants compared with glyphosate-susceptible plants [10]. The level of gene expression was positively correlated with gene copy number. Fluorescent staining for the gene showed that the amplified gene copies were present on every chromosome.

Gene amplification is one of the most common physiological responses of cells and organisms to ‘selective’ agents in their environment, known at least since 1980s [9].

Glyphosate resistance has been confirmed in 16 weed species as of 2009 [10]. The mechanisms identified so far include reduced glyphosate uptake, and/or mutations in the EPSPS gene that make it less susceptible to inhibition by the herbicide. Glyphosate-resistant palmer pigweed is the first case of resistance based on gene amplification. It confirms the ease with which resistance to obnoxious agents can evolve [9], and the futility of this ‘chemical warfare’ against nature.

Tarnished plant bug the single most damaging pest for cotton

The tarnished plant bug infested 4.8 million acres of US cotton in 2008 [11] making it the single most damaging pest for cotton. Another insect, the fleahopper ranked 5th, and infested 2.3 million acres.

The Cotton Belt of the United States, extending from the San Joaquin Valley of California to Southeastern Virginia, has largely seen off the boll weevil and tobacco budworm since the introduction of Bt cotton, which now accounts for 65 percent of the area planted with cotton (Table 1 [1]). But, as in India and elsewhere [12, 13], secondary pests are posing serious problems, especially the tarnished plant bug.

The tarnished plant bug (TPB), Lygus lineolaris, has been a cotton pest for as long as records were kept. Before 1995, it was controlled with insecticides targeting other insect pests such as tobacco budworm and boll weevil. According to researchers at the Mississippi State University Delta Research and Extension Center [14], since the widespread adoption of Bt-cotton and eradication of the boll weevil, less insecticide have been used; and as a result, the tarnished plant bug has become the primary insect pest of cotton.

Additional insect control costs are coming from increasing foliar sprays, higher technology fees and pest resistance, said Jeff Gore, research entomologist at the Delta Research and Extension Center, speaking at the 2010 Beltwide Cotton Conferences in New Orleans [15]

In 1995 planting an acre of cotton cost $12.75 to $24; in 2005, planting Bollgard, Roundup Ready cotton with a ‘Cadillac’ seed treatment would have cost about $52 an acre. Now in 2010, with Bollgard II and Roundup Ready Flex, farmers will be spending $85 or more an acre.

“In Mississippi, we have growers who are spending well over $100 for foliar insect control. You add that onto technology fees and seed treatments, you understand why our cotton acreage is decreasing.” Gore said.

To compound the problem, TPB has become resistant to several classes of insecticides, particularly in the Delta regions of the Mid-South states [14].

While TPB is a pest of cotton throughout the growing season, it is particularly damaging during the flowering period, when the pest reproduces copiously, so both adult and immature stages of TPB feed on cotton during the flowering period. Most feeding occurs on reproductive structures. The pests insert their mouthparts into squares and small bolls. It is not uncommon for TPB to cause near-total crop loss in the absence of effective control in some areas of the Delta.

Mid-South growers consulted Gore about planting a non-Bt variety, especially with the higher costs of Bt technology [15]. “We have a few growers planting small acreages of non-Bt cotton, and they’re probably going to see benefits from that.

“But if we start shifting back to non-Bt cotton, I promise you, the tobacco budworm will come back, and we don’t want to be making foliar applications for resistant tobacco budworms, in addition to treating tarnished plant bugs. The amount of money we would have to spend in that situation would be astronomical.”

TPB has been the No. 1 pest in the Mid-South for the past four to five years, and is driving a lot of cotton growers out of the Mississippi Delta, no longer able to afford the cost of sprays.

Gore revealed that spider mites are also gaining a reputation as ‘budget busters’ in the South, along with aphids and stink bugs.

Like TPB, spider mites are becoming resistant to the insecticides used to control them. “Over the past 15 years, we’ve essentially doubled our application rates with Bidrin and tripled our application rates with acephate. So we’re not only spraying more often, we’re applying higher rates that cost more.” Gore said.

He pointed out that a side-effect of relying on neoniccotinoids for plant bug control is some resistance has developed in cotton aphids. “We're starting to hear lots of complaints from consultants across the Mid-South.”

More of the same is futile

It is disappointing though predictable that the only official academic advice given to farmers is more of the same conventional practices that created the problems in the first place, spraying more and spraying mixtures of different kinds of pesticides, including those banned for being too toxic. Industry, meanwhile, is ready to sell varieties with more stacked GM traits; up to eight at double the seed price [16].

Disappointing too is the persistent effort by some governments and government scientists to promote the failed GM technology, which as I made clear, was already obsolete since the early 1980s [9]. A Sciencexpress paper (indicating quick publication, probably without peer review) entitled “Food security: the challenge of feeding 9 billion people” [17] co-authored by UK chief scientist Prof. John Beddington among others, while somewhat dismissive of current GM crops, nevertheless holds out promises we’ve heard for more than 30 years. “The next decade will see the development of combinations of desirable traits and the introduction of new traits such as drought tolerance. By mid-century much more radical options involving highly polygenic traits may be feasible.” It went on to promise “cloned animals with engineered innate immunity to diseases” and more.

Glyphosate and Roundup, still advertised as ‘less toxic to us than table salt’ in a pamphlet from the Biotechnology Institute promoting HT crops as ‘Weed Warrior’ [18], is in fact highly toxic as new findings indicate [19, 20] (Death By Multiple Poisoning, Glyphosate and Roundup, SiS 42; Ban Glyphosate Herbicides Now, SiS 43). Thirteen years of GM crops in the USA has increased overall pesticide use by 318 million pounds [21] (GM Crops Increase Herbicide Use in the United States, SiS 45). The extra disease burden on the nation from that alone is considerable.

India has learned bitter Lessons from Bt Cotton [22] in a saga of worsening farm suicides and, in common with the USA, an ecological disaster in secondary and new cotton pests, resistant pests, new diseases, and above all, soils so depleted in nutrients and beneficial microorganisms that they would cease to support the growth of any crop in a decade. Their only salvation is a return to organic agriculture, which has already proven far more sustainable and profitable than Bt cotton [12]. This may apply also to the USA.

A fundamental shift in farming practices needed now

The organic market has been booming in the United States despite the economic downturn. According to a new report from the US Department of Agriculture, retail sales of organic food went up to $21.1 billion in 2008 from $3.6 billion in 1997 [23] (see Fig. 1). The market is so active that organic farms have struggled at times to produce sufficient supply to keep up with the rapid growth in consumer demand, leading to periodic shortages of organic products.

(Figure 1 Growth in US organic market 1997 to 2008)

Certified organic acres more than doubled from 1.3 million acres in 1997 to a little over 4 million acres in 2005 (0.5 percent of all agricultural land in the US). In the same period, the number of organic farms increased from 5 021 to 8 493, and the average size of certified organic farms went from 268 acres to 477 acres.

So why are US farmers failing to taking advantage of the rapidly expanding market? It is thought [23] that potential organic farmers may opt to continue with conventional production methods because of “social pressures from other farmers nearby who have negative views of organic farming”, or because of an inability to weather the effects of reduced yields and profits during the transition period. This is not surprising on account of the persistent negative propaganda carried out by GM proponents, including government regulatory agencies, against organic agriculture. (See for example the recent attempt by UK Food Standards Agency to prove organic food is no more nutritious than conventional food, which backfired [24] (UK Food Standards Agency Study Proves Organic Food Is Better, SiS 44). The usual claims are that organic agriculture yields less and require more energy than conventional agriculture, and organic produce no more nutritious or healthy, but less hygienic than conventional produce. These false claims are all thoroughly refuted in ISIS report Food Futures Now: *Organic *Sustainable *Fossil Fuel Free [25], with evidence from the published scientific literature, as well as other studies.

Most relevant for US farmers is a study by Kathleen Delate of Iowa State University and Cynthia A. Cambardella of the US Department of Agriculture assessing the performance of farms during the three-year transition it takes to switch from conventional to certified organic production [26]. The experiment lasting four years (three years transition and first year organic) showed that although yields dropped initially, they equalized in the third year, and by the fourth year, the organic yields were ahead of the conventional for both soybean and corn.

Our report [25] also documents the enormous potential for reducing greenhouse emissions – even to the extent of freeing us entirely from fossil fuels – through organic agriculture and localised food (and renewable energy) systems. It is a unique combination of the latest scientific analyses, case studies of farmer-led research, and especially farmers’ own experiences and innovations that often confound academic scientists wedded to outmoded and obsolete theories, of which GM technology is one glaring example.

At about the same time our report was released, the International Assessment of Agricultural Knowledge, Science and Technology for Development (IAASTD) was also published. IAASTD was the result of three-year deliberation by 400 participating scientists and non-government representatives from 110 countries around the world [27]. It came to the conclusion that small scale organic agriculture is the way ahead for coping with hunger, social inequities and environmental disasters [28] (“GM-Free Organic Agriculture to Feed the World[”, SiS 38).

A fundamental shift in farming practice is needed right now, before the agricultural meltdown is complete.

References

1. Adoption ofngenetically engineered crops in the U.S.: Extent of adoption. USDA Economic Research Service, 1 July 2009, http://www.ers.usda.gov/Data/biotechcrops/adoption.htm
2. Super weed can’t be killed, abc news, 6 October 2009, http://abcnews.go.com/Video/playerIndex?id=8767877
3. “N.C. farmers battle herbicide-resistant weeds”. Jeff Hampton, The Virginian-Pilot. 19 July 2009, http://hamptonroads.com/2009/07/nc-farmers-battle-herbicideresistant-weeds
4. Who benefits from gm crops? The rise in pesticide use, executive summary, Friends of the Earth International, Amsterdam, January 2008.
5. 2000-2001 pesticide market estimates: usage, U.S. Environmental Protection Agency, http://www.epa.gov/oppbead1/pestsales/01pestsales/usage2001_3.htm
6. Glyphosate-resistant weeds: can we close the barn door? Weed Science Society of America, 18 November 2009, http://www.wssa.net/WSSA/PressRoom/WSSA_GlyphosateResistance.pdf
7. “’Superweed’ explosion threatns Monsanto heartlands”, Clea Caulcutt, 19 April 2009, http://www.france24.com/en/20090418-superweed-explosion-threatens-monsanto-heartlands-genetically-modified-US-crops
8. “Paraquat fights glypohsate resistant palmer amaranth”, 30 September 2009,
   http://paraquat.com/english/news-and-features/archives/paraquat-fights-glyphosate-resistant-palmer-amaranth
9. Ho MW. Genetic Engineering Dream of Nightmare? The Brave New World of Bad Science and Big Business, Third World Network, Gateway Books, MacMillan, Continuum, Penang, Malaysia, Bath, UK, Dublin, Ireland, New York, USA, 1998, 1999, 2007 (reprint with extended Introduction). http://www.i-sis.org.uk/genet.php
10. Gaines TA, Zhang W, Wan D et al. Gene amplification confers glyphosate resistance in Amaranthus palmeri. PNAS Early Edition 2009, www.pnas.org/cgi/doi/10.1073/pnas.0906649107
11. ARS survey helps growers track two key cotton pests. PHYSORG.com, 1 December 2009, http://www.physorg.com/news178912351.html
12. Ho MW. Farmer suicides and Bt cotton nightmare unfolding in India. Science in Society 45 (in press)
13. Ho MW. Mealy bug plagues Bt cotton in India and Pakistan. Science in Society 45 (in press)
14. Catchot A, Musser F, Gore J, Cook D, Daves D, Lorenz G, Akin S, Studebaker G, Tindall K, Stewart S, Bagwell R, Leonard BR and Jackson R. Midsouth Multtistate Evaluation of Treatment Thresholds for Tarnished Plant Bug. 2009, Mississippi State University Extension Service, http://msucares.com/pubs/publications/images/p2561_pics/bug_1.jpg
15. “Insect control pushes cotton costs higher”, Elton Robinson, Farm Press, 15 January 2010, http://deltafarmpress.com/cotton/cotton-insect-control-0115/
16. Benbrook C. Critical issue report: the seed price premium. The Organic Center. 2009 December. http://www.organic-center.org/reportfiles/Seeds_Final_11-30-09.pdf
17. Godfray HCJ, Beddington JR, Crute IR, Haddad L, Lawrence D, Muir JF, Pretty J, Robinson S, Thomas SM and Toulmin C. Food security: the challenge of feeding 9 billion people. Sciencexpress, 28 January 2010/10.1126/science.1185383
18. Weed Warrior Hebicide-Tolerant Crops, accessed 29 January 2010, http://www.biotechinstitute.org/resources/YWarticles/10.1/10.1.3.pdf
19. Ho MW and Cherry B. Death by multiple poisoning, glyphosate and Roundup. Science in Society 42 , 14, 2009
20. Ho MW. Ban glyphosate herbicides now. Science in Society 43, 34, 2009
21. Cherry B. GM crops increase herbicide use in the United States. Science in Society 45 (in press)
22. Ho MW. Lessons from Bt cotton. ISIS letter to Hilary Benn, UK Secretary of State for the Environment, 4 January 2010, http://www.i-sis.org.uk/lessonsFromBtCotton.php
23. Marketing U.S. organic foods: recent trends from farms to consumers. Carolyn Dimitri and Lydia Oberholtzer, USDA Economic Research Service, September 2009, http://www.ers.usda.gov/Publications/EIB58/
24. Ho MW.UK Food Standards Agency study proves organic food is better. Science in Society 44, 32-33, 2009.
25. Ho MW, Burcher S, Lim LC, et al. Food Futures Now, Organic, Sustainable, Fossil Fuel Free, ISIS and TWN, London, 2008. http://www.i-sis.org.uk/foodFutures.php
26. Delate K and Cambardella CA. Organic production: Agroecosystem performance during transition to certified organic grain production. Agronomy Journal 2004, 96, 1288-98.
27. International Assessment of Agricultural Knowledge, Science and Technology for Development, IAASTD, 2008http://www.agassessment.org/index.cfm?Page=Press_Materials&ItemID=11
28. Ho MW. “GM-free organic agriculture to feed the world”. Science in Society 38, 14-15, 2008.

× 烏有之鄉 WYZXWK.COM

您的打賞將用于網站日常運行與維護。
幫助我們辦好網站，宣傳紅色文化！

歡迎掃描下方二維碼，訂閱烏有之鄉網刊微信公眾號