Per 
A velvetleaf invasion on a maize corn field in Japan.
Subject Name: Velvetleaf
Family: Malvacae
Description: The velvetleaf ("Abutilon theophrasti") is an annual plant originally from southern Asia that has made itself known throughout North America, Europe, Korea, and Japan through seed distribution. Though not known as a global invasive species, it is particular to damage man-made crops such as maize, soybean, and cotton production. In its genus, A. theophrasti only appears during temperate conditions while other plants in the genus appear in tropical and subtropical climates. Because of its accidental introduction to the environment, it may contaminate grains and seeds in vacant lots and agricultural lands. Starting as a purplish-brown seed, it is 2-3 mm long and 1 mm thick. After being germinated, its steam grows up to 1-4 m and will shortly produce up to sixty-three leaves with heart-shaped blades with an area of 300 to 470 cm².1
In America, the velvetleaf was introduced as an essential fibre crop from England and became common in Pennsylvania and Virginia in 1829. Later on in the 1870s, interest towards the velvetleaf decreased and soon became known as a major weed. In Canada, there were small colonies of the velvetleaf until 1950 and it was in 1984 at which it majorly spread throughout three countries in Ontario, many locales in Quebec, and a location near Nova Scotia. In Japan, it already had been introduced in 918 A.D., but not as a weed. In 1980, the strains of the velvetleaf combined with multiple weed strains and became mixed with feed grains from the United States and Australia, causing the velvetleaf to become an infestation in Japan's maize fields. In Morocco and Europe, there is little information on the velvetleaf.2
A graph regarding the outbreak and invasion of velvetleaf plants.
Though it is considered an invasive species, it has little impact on social, biodiversity, and environmental conditions. It can adapt quickly to any environment it is in and it can reproduce at a fast rate which can negatively affect the area's agriculture. It can compete with any other plants within its vicinity and can transmit diseases and pests. Some of its natural competitors include the Liorhyssus hyalinus, the Niesthrea louisianica, and the Althaeus folkertsi. Due to its uncontrollable methods, it is highly likely to be transported internationally accidentally or deliberately.
Question: What are some effective herbicide combinations that can be used to contain a velvetleaf outbreak and how effective can it be when experimenting with an optimum timing of control?
Hypothesis: Some herbicide and herbicide combinations include triflusulfuron, clopyralid, and the combination of phenmedipham + desmedipham + ethofumesate. These chemicals can be most effective when given a period of five days.
Materials: Contained said substances, a notebook to record observations, safety equipment (hazmat suit, safety goggles, etc.), and a watch to record timing.
Independent Variable: Applied herbicides and combinations on fields with velvetleaf outbreaks.
Dependent Variable: The percentage of velvet-leaf control within the desired field.
Control Group: An untouched field that meet requirements for a velvetleaf outbreak.
Constants: The types of crops used during experimentation and the size of the field.
Special Testing Procedures: Four fields will be used for experimentation: three being labeled A, B, and C while X is labeled as a control group. All fields used for experimentation will be corn fields. Phenmedipham + desmedipham + ethofumesate will be applied in field A. Triflusulfuron will be applied in field B. Clopyralid will be applied in field C. There will be two timings which will be tested with: over a five day period and over a ten day period. If the first timing is used, the first treatment will be applied on the first day and the second treatment will be applied on the last day. This method will be applied on the second timing as well. Observations and data will be recorded within those timings.
Data: Phenmedipham + desmedipham + ethofumesate gave 27 to 42% control during experimentation and triflusulfuron gave 83 to 88% control during experimentation. A five day period in between first and second treatments gave 93% control with a ten-day period in between the first and second treatment only giving 77% control. When said combination was used, the velvetleaf ending up producing between 6,700 and 14,800 seeds m−2. When triflusulfuron was used, velvetleaf production greatly decreased to between 200 and 4,700 seeds m−2.3
A comparison between velvetleaf control and giant ragweed control.
Results: The combination did not control the outbreak as much as triusulfuron during experimentation as the combination only gave 27 to 42%, which is less than what percentage triusulfuron controlled (83 to 88%) making a great gap between the used substances and confirming that triusulfuron has greater control than combined substances. The control during the five day period is 93% with the control during the ten-day period being 77%, a 16% difference.
Conclusion: In conclusion, the recommended herbicide and timing for velvetleaf control is using triusulfuron over a five day period. Triusulfuron is shown to have a greater percentage of control than other substances as described to have 83 to 88% velvetleaf control. A five day period is shown to have a greater percentage of control than a ten-day period as described to have 93% velvetleaf control (using two treatments).
