Forgot to tell you that it's the attack your farm suffered from insects that makes your beans to die off instead of maturing to big beans pod. The lambda cyhalotrin will make your beans to flower very well too and pods will develop thereafter provided you spray it well with the right chemical, dose and time.

Dear janedonez, application of DD force to your beans farm is not the reason why your beans farm is failing. DD force is not a herbicide like others have stated so it can't burn ur beans. It's an insecticide too but it cannot perform the function you it to perform.
There lots of insects and worms that attack any beans even when planted at your backyarf/garden. So you need some certain insecticides to ward off these insects and let me mention it here that there is no single insecticide capable of maintaining your farm from production to harvest but rather you need combination of chemicals, right dose and application at the right time.
Please find below step by step actions needed on your beans farm.
Hint: you will need atleast the combination of two chemicals with these two reaction ingredients.
1. Lambda cyhalotrin.
2. Dimethoate.
Depending on the variety of beans you planted, I. E, the 40 days gestation type or the normal beans of 60 days gestation. What these numbers stand for is they will start flowering at those days, 40 or 60 days depending on the type.
So soon as you noticed the first flower in your farm, then you commence spraying immediately. Note, it's better to ward off insects from your farm than trying to kill them after invasion! Beans insects are very STUBORN. This spraying at the start should be done every four days interval. This should continue until pods are developed and getting close to maturity. This will be like around 5 to 6 weeks spraying. Thereafter, your beans will be noticeable now as in big beans pods but not dried yet. You can then increase the spraying interval to once in 7 days.
In mixing your chemicals, the lambda cyhalotrin component should be like 80/100mls per 16ltr spraying can. The dimethoate should be like 30 or 35mls per 16ltr spraying can too.
Example of cyhalotrin is lara force, judo, CYPERKING, cypermetrin etc
Example of dimethoate is dime force 40ec or sconpion.
So you should continue to spray your farm up until it start to dry and brown then you can stop spraying while you wait for harvest.
Warning: early stoppage of spraying can destroy your lovely beans farm so one or two weeks mistake can ruined all efforts put into your farm for 3months.
See here a sample of a very effective dimethoate.
You can reach me on belsanol@gmail.com for further discussion on beans farming please.