Learn English – “There is a significant number of computers” versus “there are a significant number of computers”

In the first example, the object contains to only one process; immediate removal of pods from harvested plants (even though pods is a multiple). Therefore, is is correct.

In the second example, the object contains more than one process; protection against contact with the disease-carrying mosquitoes and mosquito control. Its more than one, so are is correct.

In the first example, "number X" is modifying the subject "order" as part of a series. The "1" and "2" represent the place in the series:

I need RMAs for orders number 1 and number 2 (out of 5).

I need RMAs for orders 1 and 2.

I need RMAs for orders number 1 (ID# 56789) and number 2 (ID#56790).

Making "numbers" plural instead indicates that "order numbers" is the complete, more descriptive subject, similar to "tracking numbers" or "inventory numbers." That ties it directly to that item, no matter how many orders there are or in what sequence. This makes more sense if for example you provide a complete tracking number:

I need RMAs for order numbers 1234-XYZ-0987 and 1234-ABC-7890.

Of course this could also be shortened to just use "orders," which in that case is the complete subject & needs to be plural.

I need RMAs for orders 1234-XYZ-0987 and 1234-ABC-7890.