CHAP: Cotton-Harvesting Autonomous Platform

The US cotton industry provided over 190,000 jobs and more than $28 billion total economic contributions to the United States in 2012. The US is the third-largest cotton-producing country in the world, following India and China. US cotton producers have been able to stay competitive with countries like India and China by adopting the latest technologies. Despite the success of technology adoption, there are still many challenges, e.g., increased pest resistance, mainly glyphosate resistant weeds, and early indications of bollworm resistance to Bt cotton (genetically modified cotton that contains genes for an insecticide). Commercial small unmanned ground vehicle (UGV) or mobile ground robots with navigation-sensing modality provide a platform to increase farm management efficiency. The platform can be retrofitted with different implements that perform a specific task, e.g., spraying, scouting (having multiple sensors), phenotyping, harvesting, etc. This paper presents a proof-of-concept cotton harvesting robot. The robot was retrofitted with a vacuum-type system with a small storage bin. A single harvesting nozzle was used and positioned based on where most cotton bolls were expected. The idea is to create a simplified system where cotton bolls′ localization was undertaken as a posteriori information, rather than a real-time cotton boll detection. Performance evaluation for the cotton harvesting was performed in terms of how effective the harvester suctions the cotton bolls and the effective distance of the suction to the cotton bolls. Preliminary results on field test showed an average of 57.4% success rate in harvesting locks about 12 mm from the harvester nozzle. The results showed that 40.7% was harvested on Row A while 74.1% in Row B for the two-row test. Although both results were promising, further improvements are needed in the design of the harvesting module to make it suitable for farm applications.

Pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) survival on transgenic cotton in India

Background Insecticidal proteins from the Bacillus thuringiensis (Bt) marks the genetically modified cotton crop that was commercialized in India in March 2002 for the control of lepidopteron bollworms. Despite organized initial control, the pink bollworm (PBW), Pectinophora gossypiella (Saunders), adapted itself to cry toxins resulted in field control failures in 2016 and 2017. The present study was designed to understand the survival and development of PBW populations differing in susceptibility to Cry toxins on Bt and non-Bt plants. Results For assessment of infestation, populations were collected from different cotton growing states. Per cent infestation of flowers and green bolls in the study areas were in the range of 3.09–29.26 and 36–91.20% for flowers and green bolls, respectively. Among different locations highest magnitude of resistance to Cry1Ac (371.8-fold) and Cry2Ab (4214.3-fold) was spotted in late season populations of Rajkot collected from bolls. Further, in order to confirm field level resistance of surviving larvae on high and low concentrations of Cry toxins, larvae were pooled and subjected to boll bioassays. Results revealed that, none of the larvae from susceptible populations survived on BGII bolls. Although, the same populations showed a survival of 38 and 32%, which led to 80% locule damage on non-Bt cotton. Maximum survival (32%) and locule damage (70%) was observed for Maharashtra (F-H) Cry2Ab and Gujarat (B-H) Cry2Ab populations recorded 36% survival and 70% mortality, respectively, on BGII cotton and 58.33% survival and 60% locule damage on non-Bt cotton, respectively. Populations derived from survivals on low concentrations produced the lowest survival and locule damage on Bt cotton. Maximum number of mines on epicarp (2.4 mines/boll) was recorded by susceptible population on NBt cotton. Green bolls of Bt and NBt cotton did not differ in the number of mines. Conclusion It was concluded that none of the larvae from susceptible populations survived on BGII bolls. Although, the same populations showed a survival of 38 and 32%, which led to 80% locule damage on non-Bt cotton

Ongoing ecological and evolutionary consequences by the presence of transgenes in a wild cotton population

After 25 years of genetically modified cotton cultivation in Mexico, gene flow between transgenic individuals and their wild relatives represents an opportunity for analysing the impacts of the presence of novel genes in ecological and evolutionary processes in natural conditions. We show comprehensive empirical evidence on the physiological, metabolic, and ecological effects of transgene introgression in wild cotton, Gossypium hirsutum. We report that the expression of both the cry and cp4-epsps genes in wild cotton under natural conditions altered extrafloral nectar inducibility and thus, its association with different ant species: the dominance of the defensive species Camponotus planatus in Bt plants, the presence of cp4-epsps without defence role of Monomorium ebeninum ants, and of the invasive species Paratrechina longicornis in wild plants without transgenes. Moreover, we found an increase in herbivore damage to cp4-epsps plants. Our results reveal the influence of transgene expression on native ecological interactions. These findings can be useful in the design of risk assessment methodologies for genetically modified organisms and the in situ conservation of G. hirsutum metapopulations.

Organic cotton production may alleviate the environmental impacts of intensive conventional cotton production

Conventional cotton production has been associated with the extensive use of agricultural chemicals, leading to environmental and health problems, decreased effectiveness of pesticides and higher costs of production. Organic bans the use of most pesticides while providing premiums for growers, and therefore may be a beneficial alternative for growers. Unfortunately, there has been a paucity of research examining the specific practices used by organic cotton growers and the environmental aspects of those practices. This study surveyed organic cotton producers and processors to document specific approaches and techniques used in organic cotton production and processing, the environmental impacts of those techniques and challenges facing organic cotton growers. We discuss the environmental impacts of organic management techniques and methods for conserving water and reducing dependence on irrigation. We also highlight the challenges to organic production identified in the survey, including management for weeds, insects and diseases, genetic contamination of organic crops from genetically modified cotton, organic seed availability, climate change, chemical drift and marketing of organic cotton. Finally, we suggest that investing in research to produce higher-yielding organic varieties, improved methods for organic weed management, and supporting carbon-sequestering practices will improve conversion to organic production.

Behavior and development of Tetranychus ludeni Zacher, 1913 (Acari: Tetranychidae) and physiological stress in genetically modified cotton expressing Cry1F and Cry1Ac proteins

Genetically modified plants are one of the tactics used in integrated pest management - IPM. There is great concern about the impact of these plants on non-target organisms. On the other hand, there is little information in the literature on the effects of transgenics (Bacillus thuringiensis) Bt on populations of phytophagous mites, and the physiological responses that this attack promotes on plants. The objective of this work was to evaluate the biology of the T. ludeni mite in Bt cotton, expressing the Cry1F and Cry1Ac proteins. To evaluate the behavior of food and oviposition preference of the T. ludeni with Bt cotton and isohybrid. Verify if the physiological stress caused by T. ludeni’s attack is differentiated in Bt cotton. The mites were reared in Bt cotton and isohybrid, in a total of 40 replicates in the completely randomized design and the biological cycle was evaluated. The food preference and oviposition analysis were done with 10 replicates, with choice. The physiological stress was evaluated through chlorophyll fluorescence, under greenhouse conditions. The data of the T. ludeni biology were analyzed by Student's t-test, for food and oviposition preference the chi-square test was performed. Regression models were fitted for the fluorescence parameters. The model identity test was used to evaluate the differences between Bt and isohybrid treatments. Cry1F and Cry1Ac proteins have not affected the biology of T. ludeni. The photosynthetic parameters in Bt cotton plants were less influenced by T. ludeni infestation.

A Comparative Study of Field Nematode Communities over a Decade of Cotton Production in Australia

Soil nematode populations have the potential to indicate ecosystem disturbances. In response to questions about nematode interactions with soilborne diseases and whether genetically modified cotton altered nematode populations, several fields in the Namoi cotton growing area of Australia were sampled between 2005 and 2007. No significant interactions were observed, but nematodes numbers were low and postulated to be due to the use of the nematicide aldicarb. Aldicarb was removed from the system in 2011 and in 2015 funding allowed some fields to be resampled to determine if there had been a change in the nematode numbers following aldicarb removal. No significant changes in the total nematode numbers were observed, implying that the removal of aldicarb had little impact on the total nematode population size. However, an increase in plant parasitic nematodes was observed in both fields, but the species identified and the levels of change were not considered a threat to cotton production nor driven solely by altered pesticide chemistry. Additionally, greater numbers of higher order coloniser-persisters in the 2015 samples suggests that the current cotton production system is less disruptive to the soil ecosystem than that of a decade ago.