Monday, February 8, 2010

Pecans and the Pecan Weevil

Don't you just love fresh pecans? We do and wish we had room for a pecan tree in our yard but we don't. My neighbor across the street has a huge pecan tree in his yard that is quite lovely to look at. It also has the bonus of dropping lots of pecans each year. Several of these pecans somehow wind up in my garden where they quickly sprout and begin growing into trees-read more weeds to pull:( Sometimes I find the pecans before they sprout and I think of cracking them and eating them but then I notice small holes in the shells. Hmmmm, wonder what causes the holes I thought to myself.

From In the Garden
The answer to the question of what causes holes was partially solved when Volunteer Gardener aired a segment on pecan borers. I had never even heard of these insects before this show and had no idea pests would bother nuts. Duh me. Hmmm, this bears further research.

Research came in the form of shelling a large box of pecans sent to us by our sister in law in North Carolina. It seems she has a ton of pecan trees near her home that yield some bea-u-tiful and delicious pecans. So, on a recent cold winter night Mr. Fix-it and I commenced to shelling, and shelling, and shelling. There is still yet a lot of shelling to do but back to the pecan pests.

While shelling the pecans we found some of the nuts were blackened inside. The kernel was not edible at all. I didn't look closely for any pests at this point but one came looking for me. Somehow a little white worm showed itself to us-ick! I knew immediately that this was normal and nothing to be alarmed about, however it still was not pleasant. Unless you are VERY diligent with spraying insecticides you will have some pests in nut trees, fruit trees, vegetables-you name it and they might come calling when you least expect them as in the case of our pecans.

I'm not going to caution you all on the picture below because like me, you are gardeners and used to pests especially if you are hesitant to spray poisons. I am not averse to using insecticides in the right circumstances, but my threshold for a certain amount of damage allows for some pests. Some pests were what I found in the large box of pecans. No problem, I can quickly do away with that issue-and did so by throwing out the affected pecans. The rest of the batch was fine.
At first I thought these little worms were a borer, but upon further research I am pretty sure this pest is a nut weevil. Note the blackened part of the kernel. This is a very common pest and the University of Kentucky website linked in the previous sentence does a great job of describing the pest and its remedies. The website says you can cure the nuts by gathering daily then heat treating them. There are other methods too but for small infestations just tossing the affected nuts is fine.

One thing I want you all to note about this pest is that it overwinters in the ground. The eggs are laid by an insect in the nut while the nut is still on the tree. Once the nut falls to the ground and the grub is more mature it bores a hole through the nut then digs into the soil where it overwinters for one or two years. It will emerge an adult when mature and begin the cycle all over again. It is very important to clean up rubbish and leftover nuts under your nut trees if you wish to reduce this pest population.

I have a hickory tree in my garden and I try to remove those nuts each fall when I rake my yard. I've not had too much of a problem with these weevils but then again I don't try to eat the hickories so I'm really not sure if there are weevils in my nuts or not. On the other hand my neighbor might have some good pecans but the ones that blow into my are not because they are all full of holes from pests....

in the garden....

Words and Photos Property of In the Garden Blog Team,

In the Garden


  1. eww...gifted pecan are nice and the tree is beautiful but none up here.

  2. Yuk is right Tina! What a shame to spoil good pecans. The pecan crop here last year was not good at all. We are always on the watch for good pecans. Does this mean the crop from your neighbor's tree will probably have the pest again next year? Yuk again!

  3. You'd think that after 56 years of living in the South, I would have heard of these pests. I haven't! An informative post (and now I will examine pecans much more closely).


  4. I always thought that the black was because the nut did not mature...and perhaps it didn't because of the little pests...this is very interesting, thanks for sharing the research.

  5. I love pecans! I just wish we had a good spot for planting one. They can be tricky for producing nuts since wet weather in the springtime can prevent good pollination. Weevils are ugly looking little critters aren't they!

  6. IME so far growing food crops is much harder than growing flowers... so many pests. Pecan trees are very common in my area too.

  7. Good morning all! Sleeping in on a Monday is simply delicious.

    Dawn, They are pretty trees but tend to leaf out late, at least here. Makes me think it is dead every year.

    Cameron, Check it out as I kid you not. I never knew of them either until that Volunteer Gardener segment. While that was on borers I believe this to be a weevil and it came from NC-western part. Just a handful out of two huge plastic bags is not bad though. You'll know right away if something is wrong.

    Darla, Check it out. If you see pecans around your place look for the little hole in them. It is really something new to me too.

    Monica, I used to so envy the southerners because they could grow pecans when I lived in Maine. But it's okay you have chestnuts:)

    Dave, I usually have tons of seedlings come spring. A friend of a friend wishes to buy them all. Go figure. I was just tossing them. I may bring some to the swap so if you want one it will be there. The nuts are a bonus that hubby so loves but we are overloaded with trees here. I can't remember a year this tree did not produce, even in 2007. It was good the tree had not leafed out yet then.

    Sweetbay, Oh yes, what we like to eat the pests like to eat too. Bummer but predictable. When I lived in NC my neighbor had a lovely pecan tree and we'd pick up the pecans and bake pies. Never ran into these pests.

  8. Pecan trees commonly drip sooty mold, so plant them away from house, cars, sidewalks, driveways, you do not want discolored.

  9. Very good tip Donna. Trees can be so messy. I have a few here that I'll regret planting so close to my parking area.

  10. Interesting info but. A few times I have had walnuts, pecans, ect with part of the meat being black. Now I know why. After this post I now find the black meat really the big ick veres the worm!!!

  11. Not a fun thing to find in your nuts. Could be a problem for nut growers.

  12. Ewwwwww yukky too bad the good ones don't fall into your yard. Pecans make some wonderful crusts. Our neighbor has hazlenut trees Bob would love to get a few nuts from and the neighbor doesn't mind but the chipmunks and squirrels beat him to them. LOL Great and informative post Tina.

  13. I have shelled my share of Pecans and found the black meats but never the little worms! Icky poo indeed... I always wonderedy why the meats were black at times and now I know. Also why holes in some nut shells. Thanks for this info today as I am smarter now :-)

  14. I love pecans. Have shelled quite a few but never ran across this situation with exception of a little black. I just thought it didn't mature completely. Never dreamed that it was caused by a worm. Yuk. I've never even heard of it.
    I will for sure be on the look out from now on.
    Thanks for a very informative post today Tina.

  15. We have walnuts here instead of pecans. Pecans don't like our winters.

  16. Well, I have never heard of them either. People grow quite a few pecan trees in our area, but I don't know if they have the borers or weevils. They probably do, I would guess.

  17. Mom, black nut meat might mean weevils or borers for sure.

    Rosey, Nut growers probably spray their nuts regularly but definitely a possible issue.

    Linda, I just love pecans. Hazelnuts too! Nutella is a favorite hazelnut spread of ours here.

    Skeeter and Lola, I'm surprised more folks haven't found these little grublike things. To be honest I never found them before but they are a problem and lots of info on the web about them. You all know my goal is a bit of education so glad you two are feeling a bit smarter today:)

    Marnie, Walnuts may have a problem with pests too. These type weevils usually attack pecans but can go after hickories, hence I'm on the lookout. Love walnuts!

    Noelle, It is a definite possibility that your nut trees may have some. The website does say the problem seems worse after rainfall so a drier climate may make the problem less.

  18. I'd never heard of them, but not surprised to see that even nut trees have pests. Good information to pick up all the nuts that drop to prevent the weevils from spreading.
    Glad you had mostly good pecans, Yum!

  19. I grew up around a lot of hazel nut trees, and we used to collect a whole bunch right off the ground, take them into the garage and shell and eat them there. We learned pretty quickly not even to bother with ones that had holes in them. Eww... At least, the girls didn't bother with the holey ones; the boys chose them out on purpose.

  20. Tina, or anyone, have you heard that if a nut is bad a squirrel wont't touch it? I was told that when in N.C.
    We have a lot of pecan trees around here. My neighbor just gave me a gal. zip bag full of shelled pecan nut meat. That was a great thing. Lots to eat & bake with. Yummy.

  21. Great job on the research Tina. Very informative. This information is something i will use in the future I am sure. I will absolutely be sure to check the pecans more closely.

  22. Worms are the WORST! I've seen holes in our hickory nuts, but I never thought to rake up the nuts, not that we have that many, but still...

    Wish we could grow pecans up here! It's my very favorite nut of all!

  23. It's interesting how you as a gardener react with acceptance to a pest that a commercial grower might feel needs to be sprayed with tons of insecticide. I think that if all of us were a little more accepting of imperfect produce--including the occasional icky crawler--we'd be using lots less poisons in our gardens and agricultural areas. I think the earth would be a lot better off.

  24. Hi Tina~~ Thank you for dropping by my blog. I'm having trouble keeping up with all of the fabulous garden bloggers out there, but I'm here, finally. :)

    I know freezing is a good method for killing food pests. I'm sure that's a weevil larva because it looks just like the vine weevil larvae that like to eat the roots of my heucheras. White body with that telltale spot of brown on the head. Nasty critters.

    I'm a cherry fanatic and one year I was eating bunches of them off my neighbor's tree until I saw a tiny worm. GROSS. It's one thing to see them, quite another when you know you've ingested a bunch of them. I'm more careful now. :)

  25. Thanks for a very interesting and informative read Tina! I've never tried to grow nuts, so I've never really contemplated their potential problems. I guess just about everything in the garden has something that wants to eat it! Heidi.

  26. I don't have to worry about pests in pecans since we don't have pecan trees here--wish we did! But I've seen something similar in hickory nuts, too. Glad you checked carefully before making a pecan pie:)