Luke 10:2 (NIV84) He said to them, "The harvest is plentiful, but the workers are few.
Ask the Lord of the harvest, therefore, to send out workers into His harvest field."

Farming technology is amazing, isn't it? We have gotten it down to so much of a science, that fewer people can do more and more of the job of harvesting. There are however, a few crops that still must be harvested by hand (Chocolate, or Cacao, being one of them). How frustrating must it be for a farmer to have a bumper crop one year, only to be short-handed, and not be able to bring the whole harvest in! Can you imagine watching your crop die in the fields, and ultimately rot, simply because there was no one to bring in the harvest?
Jesus says that the harvest (of souls) is plentiful. In other words, there are many people who's hearts are ready to accept the good news of Christ's death for their sins, burial and resurrection to new life! This is not the kind of harvest that we can automate. This will ALWAYS be the kind of harvest that is hand picked by laborers in the field.
So He says to ask the Lord of the harvest (himself) to send out workers into His harvest field. ... I'm down with that. "Lord, could you please send people to help those people that need you? You know, send them to those harvest fields that you have, (wherever they are)." I can pray that while sitting in my lazy-boy, sipping on my morning coffee, then go on about my day feeling good about the fact that God is going to send some people to bring in the harvest...
If only Jesus stopped with verse two.
Verse three starts out with one of the shortest sentences possible! Two little letters - "GO!" And yes, that is a complete sentence. You see, "go" is the verb... The subject is a "you" (understood).
So, does God want you to pray for harvesters? Absolutely! WHILE you are going to whatever field He has called you to harvest in.
Whatever your theology, the implication of this story is that if enough harvesters don't go, there are those "crops", ripe and ready, who will wither in the field.
Lord, send out workers! May our response to Christ's command be the same as Isaiah's! - Isaiah 6:8