Allotment Gardening Advice Help Chat

Growing => Growing in Greenhouses & Polytunnels => Topic started by: Marcus10 on July 25, 2012, 09:57

Title: insects on cucumbers
Post by: Marcus10 on July 25, 2012, 09:57

Hi, I have some cucumber plants in the greenhouse, which so far have yielded well. However the leaves  are very mottled and yellowing.

I assumed red spider mite.  I can see a few tiny insects on the underside of the leaves but I thought spider mite would look like pin heads or tiny dots. These are tiny, minute in fact, but look like little fine pencil line shaped, that is, elongated rather than roundish. They move quite quickly on the leaf if disturbed.

Can anyone confirm that these are likely to be spider mite or are they the wrong shape?

Title: Re: insects on cucumbers
Post by: Kleftiwallah on July 25, 2012, 10:03

Don't automatically asume it is these insects that are damaging your cuc',  I should look into a possible mineral deficiency as a likely cause - possibly magnesium.

Cheers,    Tony.

Title: Re: insects on cucumbers
Post by: Marcus10 on July 25, 2012, 10:08

Thanks , Could overwatering cause this defficiency if the compost is waterlogged?

Title: Re: insects on cucumbers
Post by: Kleftiwallah on July 25, 2012, 10:09

If you are asking if overwatering could 'wash out' the minerals, I don't think so.  But as you have mentioned 'waterlogged' that may be the cause.

Cheers,    Tony.

Title: Re: insects on cucumbers
Post by: Marcus10 on July 25, 2012, 10:16

Thanks Tony. I have just looked in my tomato book and it says too much Potassium can lead to magnesium shortage. The plot thickens. Out of lazyness I use the same water for my cucs as my toms which includes a daily feed of Chempak Tom feed, Maybe you have hit the nail on the head!

I will try an epsom salt spray.

Thanks.

Title: Re: insects on cucumbers
Post by: Salmo on July 25, 2012, 16:58

Quote from: Kleftiwallah on July 25, 2012, 10:09

If you are asking if overwatering could 'wash out' the minerals, I don't think so.  But as you have mentioned 'waterlogged' that may be the cause.

Cheers,    Tony.

A waterlogged plant will not develop a decent root system, in fact the roots can get less if it is really waterlogged. If the root system is not good it cannot take in the nutrients it needs.

Title: Re: insects on cucumbers
Post by: Yorkie on July 25, 2012, 18:31

A daily dose of tom feed seems far too frequent - is this the dosage rate on the bottle / box?

Title: Re: insects on cucumbers
Post by: Marcus10 on July 25, 2012, 21:58

Yes, daily feed after formation of third truss. I can't complain on that score since I have had loads of Toms since June. (early planting and heat from March to May)

Having done alittle more research and inspected the leaves again and magnified the insects in my daughters bug magnifier!  I think that the culprits may be  thrips.