Hello,

I'm not familiar with H. armigera per say, but in my experience (with Heteroptera eggs), humidity can be of prime importance. Have you checked for differences in relative humidity between cages with and without tomato plants?

Also, this probably isn't the case but if you are using artificial lighting that emits UV radiation, then the eggs that aren't on the plants can be irradiated. A good way to verify this, appart from checking your lamp's spectrum, is to look at the position of the eggs on the plants; if they are positioned on the bottom of the leaves or the fruits, then they are probably sensitive to UV radiation.

I hope this helps!

Agree with this point of hygrometry.

In tortricid eggs, we can have such problems with eggs oviposited on paper or tissue. They normally are glued on a waxy surface (leaf or fruit) which prevents dehydratation from the the beneath of the egg.

To overcome this we offer waxy paper or glass as oviposition material.

Hope this helps

Simple approach is to use muslin cloth for egg laying in such a way that it always retains 20 to 30% moisture. This will keep the eggs viable

We rear H. armigera and this problem is caused by males and female adult moths reaching sexual maturity at different ages (i.e. females may reach sexual maturity before males and lay eggs before they have been fertilised). I would recommend keeping large cultures (>200 individuals per generation) to avoid in breeding and leaving pupae to emerge in a cage with 50 - 100 other individuals. This way you are much more likely to get some cross over of males and females which are sexually mature. FYI this could have been answered with a simple literature search (sorry for sounding narky but this is the second time I have answered this question on research gate - a bit of googling never hurt anyone, and that is how we solved the problem). The paper you are looking for is here: http://jee.oxfordjournals.org/content/87/6/1502

Dear Asma

Non hatching in the eggs is the main problem with H. armigera. It is to be better to mate the adults in the plastic container having 10% honey solution with Vitamin E. This will provide the better egg laying. additionally,  place a twig of chick pea plant (you can use caster leave also). As the emergence of adults started, transfer the adults (male and female both) in newly prepare mating jar as above by covering it muslin cloth (Black will be better and wash it properly to remove starch it it as it help in growing fungus ). Check the jar for egg laying and transfer the eggs laid on cloth in a small plastic container. Do not forget to moist the cloth and placing a moist cotton swab in it along with a leaf of caster (properly sterized in UV). You will get the neonates within 3-4 days. The whole setup require proper humidity (around 80%) and temprature (27-29).  Hope this will help you to maintain the culture of H. armigera in the lab.

Best wishes

Dear Asma

Keep the male/female ratio at 1:1 in the mating cages, provide muslin cloth for egg laying, keep the egg laid muslin cloth in a separate jar with a moist cotton swab on the jar mouth and make sure that it stays moistened throughout. I do agree with Aislinn Pearson that males and female adult moths in Helicoverpa have different emergence time and they attain sexual maturity at different ages. Hope it will help. 

Good luck

Dear all,

I thank you for all these information. I will try to improve the method of rearing and I inform you of the results

Every lab face such problems at the beginning. Some tips for you;

1. Maintain humidity

2. Muslin cloth is ideal than any plant material.

3. Advancing only robust and healthy pupae for adult stage.

4.Sex ration should be 1:1.

5. Larger flight space for adults.

6.Adult diet should be vitamins rich.

I have messaged the protocol which we are following for rearing Helicoverpa armigera to you.