Pigeon pea Pests and their Management


Hi, welcome to the agrifunda today post on the ‘Pigeon pea pests and their Management’. As you are aware the pigeon pea is one of the important pulse crops of India and is one of the important the protein source for the vegetarians. As it is rich in protein, so not only the humans but also the insects relish greatly on this crop. And in this crop, several insect pests are known to cause the serious economic damage. But of which we are going to consider a few very important ones and then dealing with their nature of damage and their damage symptoms along with their management.



Pigeon pea Pests and their Management by agrifunda



Pigeon pea Pests and their Management:

So on the pigeon pea pest, the gram pod borer is quite serious. We can call it as a regular pest. And spotted pod borer which has now very recently started coming in a serious form. And of late also we have in a late season crop, we have the pod fly. And there is a group of pod bugs which feeds on the pods. So on the reproductive pods we do have several important pests. And of course on the leaf, we have got the leaf webber which is becoming quite serious, though not causing much economic damage but it is causing lot of nuisance. And also we have a non-insect pest that iseriophid mite, so which transmits the micro-plasma disease and leads to the sterility of the crop.

Gram pod borer:


Now coming to the gram pod borer or Helicoverpa armigera, as you are aware is one of the important polyphagous pests and highly notorious, and is it is a pest of national interest. And the adult characters, you are already aware from the lectures of the earlier crops. And the larvae, so which are the major damaging stage. So which cause the serious damage to the pods. Now one interesting thing about the caterpillar is that, so the Helicoverpa armigera occur in several color morphs. So as you can see it here, they comes in the form of darkest green to the brownish and then also to the dark blackish or the black colored. And also a mixture of the yellow and the green. So these color morphs often confuses the farmer in identifying the pest.

Nature of damage:

coming to the nature of damage. The caterpillars, at the young stage itself will start attacking the reproductive part, be it in flower bud or the flower. As you can see it here the young larva which is feeding on the flower bud. And a peculiar feeding nature of the caterpillar is that, it puts a part of the head and the thorax inside the damaging part and then feeds, whereas the rest of the body will be outside. And whereas the grown up caterpillar will feed on the developing parts and feeds on the developing seeds. And as a result we get a very peculiar, the circular holes on the pods and wherever the seeds have been eaten. So if the damage is by the Helicoverpa, then we see more than one such holes on each pod. So which is a very peculiar damaging symptom.

Management:

for management it is always better to go for monitoring the pest. So very regularly so using the sex pheromone trap. And if you put the sex pheromone trap, the number of traps to be put
should be around 5 traps per acre. And the economic threshold level for it is that 5 adults per trap, if they are actually caught, then that is an economic threshold level. Or if closely monitor and count the eggs. There are 2 eggs per plant or 1 larva per plant. So one should resort to the management.
So the preventive measures. Always go for the deep summer ploughing. So which is quite effective as it destroys the pupa which are hidden in the soil. And also mix the jowar seeds or the red gram, I mean the 100 g of jowar seeds you mix along with the red gram seeds and then sow them, so which also act as what is called as the live bird perches, for enabling the birds to sit on the perch and then feed on these
larvae. If not you can also go for erecting the artificial bird perches @ 20 -25 per acre, and this is going to help the birds to devour the larvae.
As far as possible try to take up the sowing very early. So as some of these the crop stage is going to escape, before this pest becomes quite more or pestiferous. Then grow sorghum as an intercrop. So intercropping with any kind of cereals is also going to reduce the pest, as it is going to hinder the movement of the moth and as well as the caterpillar. Then collection and destruction of the grown up larvae from the plant as a mechanical collection is quite effective in removing it.
Then the best, the other management practices would be. Go for the application or the spraying up of the virus, that is HaNPV @ 250 larval equivalent per hectare. And care should be taken that while you are actually spraying the HaNPV; add ½ kg of jaggery to it and as well as 1ml of the boric acid. So this boric acid will actually protect the NPV virus from the UV rays and whereas the jaggery or the brown sugar is going to act as a phago stimulant and then facilitate the larva to feed and then imbibe the virus. And the Nomureae rileyi as a fungal pathogen is also found to be effective and sprayed at 2-5g per liter. And the botanical such as the Azadar/achtin, that is a commercial neem based insecticide @ 2ml per liter is also quite effective. So as a last resort we can also go for the application of any one of these chemicals, which are the novel insecticides and as well as some of them are the green molecules, and which can effectively control this pest.

Then next, a very important the pest on this crop, which has quite recently become quite a nuisance or pestiferous is the spotted pod borer. Which is also called theMaruca vitratatypically. And this pest in the last few years is causing a huge damage to the flower, flower buds, and as well as the young pods. So the Maruca vitratais a moth which is a slender bodied moth, and the fore-wing has got a white dumble shaped patch on it and the hind-wing, the basal half is whitish and whereas it has a marginal brown patch on the wing. And as the name indicates, the caterpillar is milky white or light yellowish in color. It has got lot of spots on its body and that is why the name is the spotted pod borer.

The infestation starts at the flowering stage itself. And as you can see that it has a peculiar habit of webbing the flowers together, the neighboring flowers and as well as the young leaves. And then feeds internally. So internally if you open the pod, then you see the caterpillar which is Feeding on the developing grains, and such developing grains will have a shriveled appearance. And this reduces not only the quality but also the yield in the crop.
for the management it is always better to collect and destruct the webbed flower or the flower buds or the young pods and there by you can mechanically remove this pest to a larger extent. And then go for application of any of the chemicals at the recommended dose so which is effectively going to control this pest.
Then in the later stage of the crop when the pods are in the maturing stage. When the grains are getting matured, we have one more pest which is the fly. We call it as a pod fly.
So the red gram fly is the Melanagromyza obtuse is becoming quite serious nowadays in the late stage. So this looks like a housefly but slightly stouter in the size. And this lays the eggs singly and these eggs are laid inside the pod as it has got a very sharp ovipositor. And the creamy colored maggots which feed on the developing grains and the pupation takes place inside the pod itself.
As you can see here the damaging symptoms. Externally you don’t see any kind of a damage on the pod. But upon a careful observation you might see some of the ovipositional damage. Or sometimes you see that when the maggot before going to the pupation will scrape the pod riant and then go for pupation, which indicates the emergence of the adult. Such pods are opened, then you can see the shriveled seeds and the light brownish pupae which have been found beside the seeds. And these seeds are affected. You can see the maggot stage and as well as the pupal stage inside. So it has become quite serious, as externally it doesn’t show any symptom. But only after harvesting you notice the damage by this pest.


Management

so it is always better to go for an early sowing and as well as the short duration variety. As this is found to be occurring in the late stage of the crop, or in the December or January stage. So during that stage before if the crop completes its pod maturation, then that variety is going to escape that act by this pest. Or else go for foliar application of any of these chemicals at the recommended dosage. And while you are spraying the chemical, so please add jaggery to the insecticide, as this is going to act as a phago stimulant to the adult fly. And so when it feeds, it is going to be killed.

So in the vegetative stage of the crop, we notice another pest. So which is very recently becoming quite nuisance. And it is called the leaf webber. So the leaf webber or Grapholita critica as a Tortricidae group is a small moth. And it is a dark greyish or brownish in color. And the peculiar nature of the damage is the creamy colored larva. So it is found folding the leaves and then scraping the leaves inside. Or it also webs the neighboring leaves together, and then scrapes the chlorophyll content. As a result the leaves and as well as the part of the plant will show the white papery appearance and then loss of chlorophyll content. Thereby to a certain extent it reduces the plant vigor also.
As a management, always collection and destruction of the pest, I mean or the webbed part of the plant, that is webbed leaves is better. Or go for spraying of any of the chemicals in the recommended dosage.
Now on the pod we also notice the sucking pest. So that is pod bug. There are 2 species that are quite common. Either they may occur together or they may occur individually. So they are the Riptortus pedestris is a one species and Clavigrella gibbosa is another species. And both the
adults and as well as the nymphs, so they are found on the pods, and then they continuously suck the sap by piercing the stylet inside the pod. And then so sucking the sap from the developing grains. And as a result if the infestation is too heavy, externally we see that there is a drying up or shriveling up of the pod. And internally also the grains are going to be shriveled and deformed, and they lose the market value, and also reduces the yield.


control of this pod bug

For the control of this pod bug. Application of any of the commercial neem based insecticide @ 2 ml per liter is going to manage the pest.
Now another important non-insect pest that is occurring on red gram is the eriophid mite. We call it as Aceria cajani. And the image that you are seeing is actually the sun image; the scanned electron microscope image. The very minute and microscopic non-insect pest, so which is found feeding on the leaves. And not as a feeding direct damage. It acts as a vector for transmitting the micro-plasma disease, and thereby it causes what is called the sterility in the crop. As you can see the young leaves will show a typical symptom of the mosaic appearance, and also they have this what is called as these mosaic appearance are going to congregate, and then such crops are fail to produce any flowers at all. So the plants become completely sterile and do not produce any flowers or the pods to it.
So the micro-plasma disease which is transmitted by this mite is going to cause a lot of damage to it. So application of any of the Acaracide can control this eriophid mite. And we need to prevent the occurrence of this pest, so well before the transmission of the disease.
Thank You.

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