I have a doubt from longtime. we have been said for sesamia inferens(pink stem borer) in maize the carbofuran granules should be appled in whorl. but how does that reach the stem borer? how does that granules work? why they should not be applied to soil? kindly help me understanding this.
I have read few articles on systemic insecticides on net. The gist of them is when pesticide is applied to soil where roots absorb and then moved to all the plant parts, the residual effect stays for at least 8 weeks but the process is little bit slower than foliar application.
In foliar application the pesticide is absorbed immediately and faster action but the residual effect is low. It will be only for 2-3 weeks.
coming to carbofuran, it is contact and systemic as per the article in wikipedia.
So my question is still why foliar? why not soil?
And another question is how does granules in whorl release pesticide? I think for granules to release pesticide they have to get in contact with water, where does the water come from in maize whorls?
Let me venture an educated guess.
Typically contact pesticides are prescribed for caterpillar pests, especially the larger ones, since the dosage needed for a systemic chemical to be absorbed by the plant, then ingested by the caterpillar and to effectively kill would be very large. It also seems to make more sense to just address the area where the caterpillar would reside than poison the soil and plants. Additionally, carbofuran seems to be absorbed by the leaves, so the whorl leaf area where the borer is may have high concentration of the chemical.
I think Carbofuran granules are quite small and hence have a large surface area. Moisture would come from the plant secretions, dew and even the insect body surface.
All said, apply extreme caution as Carbofuran is extremely toxic to vertebrates; I read one grain can kill a bird and its effects are huge on all animals and humans.
I cannot coment on your question but I can suggest you a bio pestiscide it is called “Nomuraea rileyi” This is a fungal micro organism.
There is one more such"Metarhizium anisopliae"
UAS has Dharwad has developed in usable form. It is very cheap 75/- for a pack of 1/2kg. 10Gm for 20 ltiters of water.
Advantage of this pesticide is,
1.It is organic.
2. Frequency is only once for a crop.
3.Not harmful for any human beings.
4. Can be reproduced by yourself by collected corpse of insects and drying it and powdering it.
5. Stem boreres, pod borers,… all pests can be controlled by this.
6. Cheap compared any other poisonouse pesticides (1:6 times)
This just an alternative for your option.
can somebody explain me the life cycle of pink stem borer? I mean where it lays eggs and where it pupates? how hatched and grown larve feeds on plant and which part of the plant? How does this enter the stem kind of things. if this is available on some website kindly point to it. Thanks in advance.
[quote]Newly hatched larvae remain in group behind the leaf sheath and begin chewing on the stem and epidermal layer of the sheath. Some migrate to neighbouring leaf sheaths, while others penetrate the stem.
Whorl feeding of larvae results in rows of oblong holes in unfolding leaves unlike round shot holes produced by Chilo partellus.
Cob and Tassel at oneplace Later they bore in to central shoot resulting in the drying up of the growing point and formation of dead heart in young maize plant as a result of larval feeding some times the bottom internodes show circular ring like cuts.
Severe damage causes the stem to break. Severely infected plants due to stunting may appear to have some times the cob and tassel at one place.[/quote]
From a pretty good reference here: ikisan.com/Crop%20Specific/E … ment.shtml
I have visited that site. I thought i could get more detailed one. any way thanks.
its because carbofuran 3G is systemic insecticide and the results shows that they are more efficiently adsorbed by roots in maize although much more due its toxicity towards stem borer.