Why is cotton genetically modified

The use of biotechnology in cotton has made a significant contribution to the dramatic reduction in insecticides applied to Australian cotton crops. Before the availability of Bt technology, most Australian cotton crops were typically sprayed 10 — 14 times per season with insecticides for Helicoverpa spp.

Crops are now typically subject to no more than 0 - 3 insecticide treatments per crop. IPM strategies use a combination of natural controls and pest-specific chemistry to further reduce pesticide use. Moreover, the cross-pollination rate depends, to a large extent, on the climatic and ecological condition that determine, for example, the patterns of activity and abundance of insect species carrying out pollination and pollen flow Llewellyn et al. However, in our study we observed that the most imminent risk of gene flow is not by pollen, but by seeds spilled during transportation.

Cotton-seeds can be efficiently dispersed by either wind or water. During several field visits to the cotton productions areas, it was observed that there is a very strict control and biosafety measures during the movement of the GM cotton-seeds from the seed-companies to the fields.

The GM seeds arrive in closed packages and closed vehicles. However, after the harvest, such controls relaxed, and the seeds are transported to the gins in open vehicles that spill seeds in the roads.

Volunteer plants can grow from spilled seeds and have been observed in the edge of roads. Sanity authorities and seed companies are in charge of removing the volunteer plants, but unnoticeable escapes are always possible. From the two scenarios of cultivated cotton without volunteers and with volunteers , we further elaborate an ENM as described in Methods. It can be seen that the conditions in which GM cotton is planted blue dots are very restrictive and conditions are clearly differentiable from the rest of the cotton species wild in black, gray, and colors.

However, the presence of GM volunteers red dots in environments other than GM growing regions demonstrates the environmental plasticity of GM cotton, and broadens the environmental component of the GM cotton niche toward the environmental space occupied by wild species.

In Figure 4 we show the potential distribution of GM and wild cotton. According to the models describing the two possible scenarios without and with volunteers , this figure shows that the presence of volunteers significantly expands the niche of GM cotton in its geographic component Figure 4. Figure 3. Conditions in which GM cotton is planted blue dots are very restrictive and differentiable from the rest of the cotton species wild in black, gray, and colors. GM volunteers are represented with red dots.

Figure 4. GM cotton distribution models adding the presence of volunteers. In green: potential distribution of GM cotton. In yellow: potential distribution of wild cotton. Black dots indicate the records of GM cotton plots while red dots indicate the records of volunteer plants used for the elaboration of the models. It is important to mention that Wegier et al. These authors proposed that the gene flow may be possible through the dispersion of seeds Wegier et al.

Hence, it is necessary to follow up the monitoring of hybrid populations and implement sensitive methods such as RT-PCR and digital-PCR to evaluate in detail the changes in transgene frequencies in these populations Holst-Jensen, ; Fraiture et al. Overall, farmers pointed out that the use of GM cotton resulted in better pest control and easier pest management. Also, higher yields of GM cotton were generally mentioned.

The reasons for stopping the planting of non-Bt conventional seed include difficulty for controlling pests and high costs of insecticides. According to the opinion of the farmers, GM cotton showed higher yields and required less use of insecticides and crop management. Nevertheless, according to farmers' opinions GM cotton-seeds are expensive and the use of herbicides is higher.

In addition, farmers agreed that the highest yields of GM cotton are due to better seed quality and favorable weather conditions. Cotton is planted in the arid areas of northern Mexico, where adverse weather conditions are prevalent, including the lack of water, extreme temperatures, drought, and frost.

Inputs such as special planting equipment, irrigation, and fertilizers result in high production costs. In addition, an increase in seed prices, machinery, and fuels in recent years exacerbated the production costs. The high operation costs as well as fluctuations in international fiber prices, led to a large fluctuation in the total cotton area planted.

For instance, in the total cotton area in Mexico was reduced to , ha, due to the decrease in international prices and the increase in input costs. However, the cotton area was doubled to , ha in due to an increase in international fiber prices. The decrease in grain prices could be another important factor that favors cotton growing for some farmers.

Ten percent of the farmers considered that GM cotton is not profitable. Furthermore, due to current pest populations observed for the past few years, they considered that current pests are not necessarily controlled by GM varieties.

From the point of view of the effects on human health, farmers have a positive perception about the adoption of GM cotton. They believe that the intoxication cases due to chemical pesticide exposure have been reduced with the adoption of GM cotton.

They reported less intoxication cases due to a lower use of chemical insecticides Nava-Camberos et al. In order to analyze changes in pest and weed management after the adoption of GM cotton a survey was applied to technical advisors specialized in cotton management.

With respect to the management of weeds and herbicides, the responses of the technicians indicated that glyphosate is practically applied to the entire cotton growing area in Mexico at least once during the production cycle. The main weed species associated with cotton are field bindweed Convolvulus arvensis L. Roth, palmer amaranth Amaranthus palmeri S. Wats, johnsongrass Sorghum halepense L. Technicians indicated that problems associated with weed management were reduced in Mexicali and La Laguna, but they were increased in the state of Chihuahua, where the control of weeds with glyphosate was qualified as low.

Sixty two percent of the technicians indicated that they have observed changes in the response of weeds to glyphosate. This response of the weeds implies the need of a dose increase of herbicides in order to have an effective control in the most difficult weeds.

Before the use of Bt cotton, the Lepidoptera complex P. The reported insects list is presented in Table 1 , where it is observed this drastic drop in lepidopteran counts, while other insects such as aphids, mites, weevils, thrips, and whiteflies increased in counts by the technicians. The technicians consider that the pressure of the Lepidoptera complex was very high before the use of GM-cotton and now it has effectively been reduced.

After 20 years of using Bt-cotton, the interviewed technical advisors have observed drastic changes in the composition of insect pest species. Currently, the most important are Anthonomus grandis, C. Due to environmental differences in the cotton growing regions of Mexico, it is difficult to rank the overall importance of pests.

For example, whiteflies are of primary importance in Mexicali, Sonora, and La Laguna, but in Chihuahua, they are considered a secondary pest. Conchuela C. This eradication is due to the joint A. After using Bt-cotton, P.

Regarding the number of total insecticide applications, the technicians reported a significant decrease due to the use of GM cotton. Due to the effectiveness of Bt-cotton, and its high rate of adoption in most of the growing areas, in Chihuahua and La Laguna the synthetic insecticides sprays have been reduced to 3.

Nevertheless, in other regions such as Mexicali and Sonora that showed high pressure of pests that are not targeted by Bt-cotton whiteflies, Lygus bugs, and boll weevils the insecticide sprays are still high. Different lines of evidence indicated that the use of GM cotton has contributed to reducing the number of insecticide applications necessary to achieve adequate control of lepidopteran pests in the cotton regions of Mexico.

Cotton is one of the crops in which the greatest amount of pesticides is applied in the world, so the alternative of using Bt-cotton represents an advantage from the environmental point of view Abedullah et al. It is known that the use of pesticides can have negative impacts on the quality of water and soil, human health, aquatic species, and beneficial insects and other organisms Boatman et al.

According to most farmers, GM cotton in Mexico, despite its costs, is still economically profitable and is one of the main income sources in the municipalities where it is planted. In those places, GM cotton seems to ensure production, and prevent losses by lepidopteran insect pests, while reducing costs and labor activities as well as the use of vehicles to spray pesticides Skevas et al.

The impact on crop yield has also been significant since in Chihuahua, La Laguna and Mexicali the yield increments are 1. It is difficult to illustrate the agronomic advances that the cotton industry has experienced in recent decades without also involving factors such as the improvement of seeds, the better use of water and fertilizers. Great effects are the result of better training of the agricultural technicians and government campaigns for crop health.

Pest eradication is an additional benefit of this technology. For example, since it has not been necessary to apply insecticides against P. It is calculated that the P. Few studies have analyzed the effect on human health and the environment of GM cotton. Adoption of Bt-cotton reduced acute pesticide poisoning in farmers in China and India Hossain et al.

The compounds present in the pesticides used in conventional crops tend to accumulate in human tissues and are very dangerous for workers if the appropriate safety equipment is not used. As mentioned before, different data and our surveys indicate that the intensity with which pesticides were used before GM cotton was very high. The intense use of broad-spectrum insecticides in conventional cotton was highly toxic, since those compounds affect many kinds of animals, including humans, and usually have high permanence in the field, affecting food chains of predators, parasitoids, and pollinator insects.

Annual crops such as cotton require a field season comprised of 6—7 months and involve the intensive management of both weeds and insect pests. The Cry toxins produced by Bt that are expressed in different cotton events Bt cotton are specific to insects of the order Lepidoptera. These toxins are active against common cotton pests such as P. Thus, the control of other pests of different insect orders that attack cotton such as the coleopteran A. It is important to note that formulated insecticides based on Bt are used in integrated pest management IPM and organic agriculture because of their high specificity.

The results of numerous studies with Bt toxins show that when non-target organisms are exposed to Bt toxins in similar amounts, or higher than those produced by the Bt-crops, they are not affected Zwahlen et al. Among the most detailed studies are those in which a pest e. Due to the high effectiveness of Bt cotton against the most important lepidopteran pests, the damage induced by these Lepidoptera complex in Bt cotton is substantially smaller, or non-existent, when compared with the damage that they produced on conventional cotton if they were not controlled by chemical insecticides.

However, the reduction of lepidopteran pests in Bt cotton may result in an increase of other cotton pests that are not controlled by Bt cotton. This phenomenon has been observed worldwide Wang et al. However, it was also reported that the lower use of chemical insecticides promotes the increase of natural enemies than can decrease populations of other non-target pests Tian et al. This increase of secondary pests apparently has been erroneously interpreted as an undesired effect of Bt cotton Wang et al.

Nevertheless, farmers generally control outbreaks of secondary pests with broad-spectrum insecticides. This practice, although effective against the target insects, also kills beneficial organisms. It has also been shown that populations of non-target organisms may fluctuate in conventional cotton fields compared to those of Bt cotton, since the density of a pest may have consequences on the abundance of predators and parasitoids Romeis et al.

The reduced applications of the broad-spectrum pesticides may favor the increase of beneficial insect populations. However, a lower number of lepidopteran eggs and larvae in Bt cotton can affect the availability of food and hosts of natural enemies. Since the vast majority of these biological control agents have broad diets, the decrease in eggs, and larvae of lepidopteran insects affects their populations only temporarily Theiling and Croft, ; Bradbury and Coats, ; Pisa et al.

Key target pests H. Among them, insects of three orders Hemiptera, Thysanoptera, and Diptera and three families Aleyrodidae, Anthocoridae, and Thripidae were the most abundant. At the trophic level, the total number of entomophagous and phytophagous insects was similar in both types of cotton.

However, the non-Bt cotton presented a reduced diversity index, after several applications of insecticides Nava-Camberos et al. One of the most important economic risks of genetically modified crops is the evolution of resistance to Cry proteins by insects Tabashnik et al.

In the case of Bt crops, the evolution of resistance to these crops has already been reported in different parts of the world in Bt corn and Bt cotton that express a single Cry protein Tabashnik et al. Join Today. Member Directory. Have a Voice. Membership Eligibility. Benefits By Sector. Member Savings. VWR, Part of Avantor. Save with BIO. Popular blogs. BIO Statements.

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In our interviews, which included Monsanto representatives, participants said it was difficult to challenge the success narrative. Concerns they raised were often silenced or left unexamined. At times, their expertise was dismissed. Evaluation studies had additional problems, particularly with regard to the differential impacts of GM cotton. Previous research in Burkina Faso has detailed how local dynamics can determine the extent to which a farmer profits from cotton production.

This additional seed cost resulted from complex relationships between farmers and cotton company employees who often belittled small-scale farmers. These dynamics and additional costs were invisible to overly narrow evaluation studies. But Monsanto received far more than this. Monsanto also received this inflated payment irrespective of the actual performance of the technology, since it was paid according to the number of hectares planted.

Monsanto profited more than was agreed to in the contract, and assumed none of the risk shouldered by cotton companies and farmers. Monsanto also benefited from a reliable GM crop success story.