APS has registered its meeting with the Department of State, which should help you with your visa application.
Recently, the U.S. has updated its visa policies to increase security for citizens and visitors, so the process of applying for your visa may have changed from the last time you applied or may take longer. If you have any difficulty obtaining a visa for the meeting, please report your case to the Department of State and specifically mention The American Phytopathological Society Annual Meeting. Please visit http://www.unitedstatesvisas.gov/ http://www.unitedstatesvisas.us/ or https://travel.state.gov/content/travel/en.html for official information.
The Department of State encourages you to apply for your visa as soon as possible. Some consulates may have backlogs in scheduling visa interviews so applicants should contact the consulate to find out how long the wait is for an interview. Visa wait times are available at http://travel.his.com/visa/tempvisitors_wait.php.
Letter of Invitation are provided to international attendees once registered for the meeting. When a registration is successfully completed and paid, a confirmation e-mail is sent to the registrant from The Multisoft Group where a link is provided to the registration invoice/receipt. (Look for this confirmation e-mail in regular and junk e-mail files in case it is delivered there.)
On the invoice/receipt page of the registration there is an option for “Download Invitation Letter” on the left side of the page. Click on this link and print the invite letter.
The International Visitors Office is also a great resource for information about your visa. Visit http://nationalacademies.org/visas.