How kill bugs/eggs on beans for planting

Question

The beans (pole beans) that I save to plant the following year always end up with multiple holes from bugs by the time spring rolls around. The beans still sprout and grow fine, but I'd rather not have the bugs. I gather up quite a few beans at the end of the season and stash them in an envelope in the garage over the winter (mild calif. temperatures). No pests are visible when I put away the seeds in the fall, so I guess the eggs are hiding in the beans from the beginning.

From the internet, it seems that they might be "weevils". Many internet sites on how to save seeds, but I haven't seen one that tells how to stop bean bugs. Have found advice to put seeds (in general) in freezer to kill pests, but they also mention beans in specific may be harmed or killed by freezing unless extremely dry. (Dry enough to "shatter": I don't think mine ever get that dry).

Any tips how to get my seed beans clean & bug free? Just to be clear, I am not trying to get rid of any kind of infestation in the garden while it is growing. I just don't like the aesthetics of opening my seed envelope in the spring and finding the beans riddled with holes and a thick layer of insect droppings, powdered bean dust & maybe dead bugs at the bottom. Even though the beans do germinate and produce just fine, and I don't see the bugs alive in the garden during the summer.

Answer 1

Against Bean Weevil (Acanthoscelides obtectus) Plantwise Knowledge Bank say:

Cultural Control and Sanitary Methods

Good store hygiene plays an important role in limiting infestation by this species. The removal of infested residues from last season's harvest is essential. When small lots of beans are stored, daily turning of the storage container can significantly reduce infestation.

Chemical Control

Due to the variable regulations around (de-)registration of pesticides, we are for the moment not including any specific chemical control recommendations. For further information, we recommend you visit the following resources:

• EU pesticides database (www.ec.europa.eu/sanco_pesticides/public/index.cfm)
• PAN pesticide database (www.pesticideinfo.org)
• Your national pesticide guide

Answer 2

Without a picture all I can do is offer my knee jerk reaction to your question. There is a short period where the Flea Beetle is prolific. Tiny tiny shot holes? The best way to deal with these guys is to plant a TRAP crop nearby, somewhere in your garden. They LOVE mustards and young brassicas. They will munch on these for a few weeks leaving your 'cash' crop of pole beans alone. Otherwise they don't do that much harm and your pole beans will recover as these guys will disappear in a few weeks.

So to answer your question, without pictures and more information and guessing this is the flea beetle, those insects disappear and will reappear without any help from you every season. Your seeds will not be introducing this insect. Plant a trap crop (I make a 'salad bowl' bed with all kinds of lettuces, radish, carrots, spinach, mustards, kale) that I swear these little guys love to eat and never bother my beans, even my broccoli/cauliflower...or anything else. Kind of cool. I mix all my salad green seeds in a shaker and shake over the top of a prepared bed to enjoy salad stuff all season long as well as feed the flea beetle for a few weeks..