The aim of this thread is to teach people everything there is to know about the budworms that are attacking your plants. The common name of this insect is the Tobacco Budworm. It has a few other names that are synonymous but that one will lead you to the most relevant information in case you want to do further research.
Identification
The tobacco budworm varies greatly in appearance so it can easily be confused with other species. Making an accurate ID of your attacker can be important because some species have built up resistances to certain treatments. Luckily for us growers, if you find a caterpillar on your plants you can be 99% sure its a tobacco budworm. If you live in Africa, Europe, New Zealand, Australia or Asia its going to be the species Helicoverpa armigera. If you live anywhere else its going to be the species Heliothis virescens. The distinction between these two species is not important however since they can both be treated using the same methods.
Most people find the larval form (caterpillar) on their plants so I won't spend much time describing the adult moth. The caterpillars are initially pale green and often have black dots covering their body. Thin dark lines run down the length of the abdomen and tend to be darker around the second and third segments. As the larva ages (progresses in instars) the black dots may develop a red border around them. The abdomen is also covered with numerous microspines that give the caterpillar a rough feel. The head capsule is nearly always a light brown color. Again I wouldn't worry too much if this description doesn't completely match up with the caterpillar you find. There is great phenotypic variation in the tobacco budworm so there can be different colors and designs.
Lifecycle
The tobacco budworm goes through an egg, larvae, pupae and adult moth stage. This is important to know so that you can realize where all potential dangers lie. Eggs are spherical and white to yellowish in color. They are about 5mm in diameter so it can be difficult to spot them. An adult female moth can lay more than 500 eggs so this is a huge problem! This problem made even worse if growing indoors since the conditions are perfect for the speedy development of the eggs and larvae. Eggs can hatch anywhere from three to 14 days after being laid. Indoors, you can expect them to hatch closer to the three day range. If possible the moth will lay these eggs close to the reproductive tissue of the host plant (our precious buds).
When the caterpillar has developed through all six of its instars (phases of growth) it will burrow 1-7 inches into the soil and begin to pupate. Don't let this happen! It will probably take 15-30 days for a caterpillar to mature so you have plenty of time to keep a look out for these things. Keep in mind though that when the caterpillars are very young they are only a few centimeters long and will be similar in color to the plant. Regardless of how vigilant you may be, never reuse soil that was involved in an infestation. Keep bags of unused soil closed so budworms don't develop secretly and surprise you in the next grow.
The adult moth is a light brown color. The banding on the wings is different depending which species you're talking about but just to be safe kill any moths that make it into your grow room.
Management
As with many other problems, the best method of managing these pests is to prevent them from entering into your grow space in the first place. Do don't bring anything from outside into your indoor grow. This includes soil, pots, gloves, clothing thats been touched by wild vegetation and ANYTHING else. Any of these items could be carrying eggs.
If you have an outdoor grow or you failed to keep your indoor grow pest free and you come under attack from the budworm there is still hope! Bt insecticide can save the crop as long as you act quickly. This insecticide is actually a bunch of tiny bacteria! Bt stands for Bacillus thuringiensis, a bacterium that produces a protein deadly to the tobacco budworm. The protein interacts with a intestinal lining of the caterpillar, paralyzing its digestive system and preventing it from eating. This will take effect in a few hours after ingestion. Notice I said ingesting and not contact. This is your biggest problem as it will require frequent applications of the insecticide. If the budworms have burrowed deep into your dense buds they will continue happy munching on your plant without eating any of the bacteria. Combat this by physically checking each bud site for holes (I know its a bitch). Pick out the bastards in the evening hours when they are least active. Spray your Bt all over the plant until it is dripping and pray you get them all. Since the bacteria must be ingested ONLY the larvae are vulnerable and that is the reason you must keep applying the insecticide. Eggs must hatch before they can be killed. Adults and pupae should be killed manually if found.
On a side note, if you are growing outdoors and are conscientious of the environment around you (as you should be), you don't need to worry about harming any nontarget organisms with the use of Bt. It specifically attacks caterpillars like the budworm and nothing else.
Releasing natural predators into your grow room can also serve as a secondary method of eradication. Some wasps, the bigeye bug, damsel bugs, minute pirate bugs and spiders are known predators. I've heard that ladybugs and praying manta can also help.
Identification
The tobacco budworm varies greatly in appearance so it can easily be confused with other species. Making an accurate ID of your attacker can be important because some species have built up resistances to certain treatments. Luckily for us growers, if you find a caterpillar on your plants you can be 99% sure its a tobacco budworm. If you live in Africa, Europe, New Zealand, Australia or Asia its going to be the species Helicoverpa armigera. If you live anywhere else its going to be the species Heliothis virescens. The distinction between these two species is not important however since they can both be treated using the same methods.
Most people find the larval form (caterpillar) on their plants so I won't spend much time describing the adult moth. The caterpillars are initially pale green and often have black dots covering their body. Thin dark lines run down the length of the abdomen and tend to be darker around the second and third segments. As the larva ages (progresses in instars) the black dots may develop a red border around them. The abdomen is also covered with numerous microspines that give the caterpillar a rough feel. The head capsule is nearly always a light brown color. Again I wouldn't worry too much if this description doesn't completely match up with the caterpillar you find. There is great phenotypic variation in the tobacco budworm so there can be different colors and designs.
Lifecycle
The tobacco budworm goes through an egg, larvae, pupae and adult moth stage. This is important to know so that you can realize where all potential dangers lie. Eggs are spherical and white to yellowish in color. They are about 5mm in diameter so it can be difficult to spot them. An adult female moth can lay more than 500 eggs so this is a huge problem! This problem made even worse if growing indoors since the conditions are perfect for the speedy development of the eggs and larvae. Eggs can hatch anywhere from three to 14 days after being laid. Indoors, you can expect them to hatch closer to the three day range. If possible the moth will lay these eggs close to the reproductive tissue of the host plant (our precious buds).
When the caterpillar has developed through all six of its instars (phases of growth) it will burrow 1-7 inches into the soil and begin to pupate. Don't let this happen! It will probably take 15-30 days for a caterpillar to mature so you have plenty of time to keep a look out for these things. Keep in mind though that when the caterpillars are very young they are only a few centimeters long and will be similar in color to the plant. Regardless of how vigilant you may be, never reuse soil that was involved in an infestation. Keep bags of unused soil closed so budworms don't develop secretly and surprise you in the next grow.
The adult moth is a light brown color. The banding on the wings is different depending which species you're talking about but just to be safe kill any moths that make it into your grow room.
Management
As with many other problems, the best method of managing these pests is to prevent them from entering into your grow space in the first place. Do don't bring anything from outside into your indoor grow. This includes soil, pots, gloves, clothing thats been touched by wild vegetation and ANYTHING else. Any of these items could be carrying eggs.
If you have an outdoor grow or you failed to keep your indoor grow pest free and you come under attack from the budworm there is still hope! Bt insecticide can save the crop as long as you act quickly. This insecticide is actually a bunch of tiny bacteria! Bt stands for Bacillus thuringiensis, a bacterium that produces a protein deadly to the tobacco budworm. The protein interacts with a intestinal lining of the caterpillar, paralyzing its digestive system and preventing it from eating. This will take effect in a few hours after ingestion. Notice I said ingesting and not contact. This is your biggest problem as it will require frequent applications of the insecticide. If the budworms have burrowed deep into your dense buds they will continue happy munching on your plant without eating any of the bacteria. Combat this by physically checking each bud site for holes (I know its a bitch). Pick out the bastards in the evening hours when they are least active. Spray your Bt all over the plant until it is dripping and pray you get them all. Since the bacteria must be ingested ONLY the larvae are vulnerable and that is the reason you must keep applying the insecticide. Eggs must hatch before they can be killed. Adults and pupae should be killed manually if found.
On a side note, if you are growing outdoors and are conscientious of the environment around you (as you should be), you don't need to worry about harming any nontarget organisms with the use of Bt. It specifically attacks caterpillars like the budworm and nothing else.
Releasing natural predators into your grow room can also serve as a secondary method of eradication. Some wasps, the bigeye bug, damsel bugs, minute pirate bugs and spiders are known predators. I've heard that ladybugs and praying manta can also help.
