Citrus grubs

[deadbeat]

Just noticed these grubs on my new kumquat bushes, only going to be stalks left if I don't get rid.

On my existing bushes I can accept some leaf munching and once established are ok.

On the new ones I have wrapped a very sticky tape around the trunk and now hope that this'll work in detering them.

 

Does anyone have a better solution to this problem? Just planted a grapefruit and noticed some damage so wrapped this as well.

All informed information welcome.

 

Cheers

[deadbeat]

[IvorBiggun2]

Its a 'Lime Caterpillar'. You can spray your citrus with Bacillus thuringiensis. It's a commercially available biological control for caterpillars on citrus.

[deadbeat]

Just ordered some from Lazada,

Thank you.

[djayz]

I spray wood vinegar regularly to deter a lot of pests. Also, time permitting, I just pick the grubs off by hand and chuck them in the fish pond - a little treat for the fish. 

[drtreelove]

On 6/19/2024 at 9:53 PM, IvorBiggun2 said:

Its a 'Lime Caterpillar'. You can spray your citrus with Bacillus thuringiensis. It's a commercially available biological control for caterpillars on citrus.

It's a good suggestion, but some other information is important for effective contol. 

There are different strains of B.t., not all are effective for butterfly larvae. 

"Common types of Bt strains: Bt israelensis controls immature mosquitos, flies, and gnats. Bt aizawai and Bt kurstaki controls caterpillars of moths and butterflies." National Pesticide information center.

 

Also, from my experience it is most effective with 1st and 2nd instars, maybe 3rd, not 4th and 5th stages of caterpillar growth. Later instars are bigger and tougher and not as easily affected.

 

Also, Bt is not a contact spray, it has to be ingested by caterpillars actively feeding on the foliage to which the Bt has been applied, preferrably with a spreader-sticker adjuvant to keep it in place. A lite spreader-sticker may not be enough during the rainy season, a heavier sticker-extender may be needed. The insect life-cycle timing considerations are important. If you are too late, its a waste. 

 

I would add pyrethrins/pyrethrum as a highly effective knockdown spray (organic program compatible, biodegrades in 12 to 24 hours). 

 

For small plants, djayz suggestion of mechanical control, hand picking, is good, and no cost or spraying. Wood vinegar for me would be a last resort, not a regular application. It's very harsh and I'm concerned about preserving the foliar microbiome and beneficials.