Whitefly


      This is a 
particular irritating pest that is about 1-2mm in size and resembles a 
moth,they feed on the sap of the plant via a tube like mouthpiece and excrete 
honeydew.They are capable of laying up to 200 eggs without fertilzation of a male,the 
egg laying period of the female is six days,after about nine days they hatch 
into the larvae stage which is where they look like scale insects
,normally pale green in 
colour,shed their skin,lose their legs and just lie 
around feeding and 
then turn into pupae from which 
the adult fly emerges .Because of their ease and speed of 
breeding if not treated quickly they can populate a plant within days and of
course all the plants around them,once you have a lot then it becomes more 
difficult to control them as you can never seem to get every last one,so 
treatment is essential as soon as you spot them.
Control of  whitefly can be achieved by several methods,organicly by the use of the yellow  fly sticky traps hung near the infected plants which is effective and  insecticidal soap which can be sprayed and tends to prevent them flying,stops  them laying eggs and suffocates most of the colony.Some of the organic sprays  can be aquired off the web such as Gardening Naturally Whitefly Killer and Eradicoat these work by blocking the breathing holes of the insects.

     Chemicaly, frequent sprays with bifenthrin (Scotts Bug Clear Gun, Bayer Sprayday Greenfly Killer Plus, Doff All-In-One Garden Pest Killer), plant extracts (Growing Success Fruit & Veg Bug Killer, Growing Success Whitefly Killer or Agralan Whitefly Killer), plant oils (Vitax 2 in 1 Organic Pest and Disease Control, Scotts Bug Clear for Fruit & Veg), fatty acids (Doff Greenfly and Blackfly Killer,Bayer Organic Pest Control or Greenfingers Organic Pest Spray) or mineral lattice (SB Plant Invigorator) are required to control established infestations. Resistance to bifenthrin can occur.

   There are several systemic insecticides that be applied as foliar sprays or compost drenches. Imidacloprid is available as a concentrate foliage spray (Provado Ultimate Bug Killer); Bayer Provado Vine Weevil Killer 2 is a compost-applied systemic insecticide containing thiacloprid for application to the roots of ornamental plants growing in pots or containers only. A ready-diluted spray 
containing thiacloprid (Provado Ultimate Bug Killer Ready To Use). Acetamiprid can be applied as a compost drench (Scotts Bug Clear Ultra Vine Weevil Killer) on container-grown plants or as a foliar spray (Scotts Bug Clear Ultra or Bug Clear Ultra Gun) on ornamental plants only. Thiamethoxam (Westland Bug Attack) is a foliar spray for use on container-grown ornamentals.

     Biological control can be achieved by use of a natural parasite of whitefly called Encarsia Formosa  these hatch from small cards of parasitised scale and hunt the whitefly.Also there is a naturally occuring midge called Aphidoletes which can do a similar job but in both cases if the infestation is large a spray of plant extracts,plant oils or fatty acids can be used first
before their introduction but then an insecticide cannot be used while they are active.


Vine Weevil

       


          This 
is another one of those pests that can do a lot of damage but the results are 
rarely seen until the plants start to die.Most adults are 
female and can lay hundreds of eggs without the need to be fertilised by a male 
between April and September,these are laid in the soil or potting compost close 
to a suitable host plant. The damage the adult does is to the leaves of the
plant and though it can be unsightly it does not really harm the development of 
the plant.

        By far the most 
damage is done by the larvae of the vine weevil,these are white grubs about 
10mm long with a pale brown head that live in the soil and 
feed on the roots of the plants,also known to burrow into tubers and corms.By 
eating the roots it is not immediately evident that the plant is being attacked 
and it is only when the leaves begin to droop that you think something is 
wrong,by this time it is too late as most of the roots have gone.Conditions for 
the eggs and the larvae are best in July and August when the soil moisture is
moderate to high so remove layers of mulch and restrict watering to a minimum.
 
 Natural  enemies of the weevil and grubs are birds,frogs,toads,shrews and hedgehogs so  they are to be encouraged but obviously this is no good in the greenhouse so  other methods must be used.Chemically you could use either Scotts Ultra Vine  Weevil Killer which gives 2 months protection and will kill the larvae on  contact and will also give control of aphids or Provado Vine Weevil Killer 2  which gives 4 months protection and 6 weeks of aphid control,both are systemics  and applied by root drench.There is also Levingtons Plant Protection compost  which is laced with Intercept which gives 12 months control and 6 months aphid  control but it means you have to grow the plants in this compost not your own  mix which may not suit you.


       Then 
there is Nemasys Vine Weevil Killer,this a nematode which develops into a 
microscopic eel worm which is a parasite of vine weevil and which enters the 
larvae and feeds on it and multiplys,this can only be used when the temperature 
is above 40 degrees F,or you could always go out with a torch on a vine weevil 
hunt at night when they are on the move as some people still do if you have the
patience.Because of heating  in greenhouses this means that all stages of the vine weevil life cycle can be  present virtually all year round,the adults are very reclusive during the day  hiding at soil level under leaves,debris and in any cracks,they cannot fly but  can climb and some people claim they can jump seeing as some of the places they  have been found,personally we have had them in the lounge climbing the wall and  on the sink unit.Because they are nocturnal movers people have been known to  check their plants in the greenhouse by torchlight claiming it is easier to  catch them this way and check under pots and staging where they hide. 


RED SPIDER MITE

         
This  is a particularly nasty insect because it is difficult to kill and there is not  really an insecticide that will completely eradicate it,normally the best thing  to do is to put the plant in the dustbin.It is not a spider it just looks like  one and is actually a mite and a microscopic one at that,they colonise the  underside of the leaves and the adult and young stages feed on plant tissue,piercing the cell and sucking out the contents thereby killing it.       There are chemical controls around but it has been found that some insects can build up an immunity to some chemicals so you can only try them.Sprays with Bifenthrin in such as Sprayday,Bug Clear Gun,Greenfly Killer Plus and All In One Garden Pest Killer also Provado Ultimate Bug Killer and SB Invigorator,insecticides containing fatty acids can also be used. This is seen by the upper side of the leaf developing small yellow / white patches  and this will progress to the leaf turning yellow and dying,as the infestation increases fine webs can be seen mainly across the shoot tips.An adult spider mite can live for up to 4 weeks and can lay 5 eggs a day,these are protected by the web from rain and condensation,the eggs will hatch in several days into nymphs and start feeding from egg to adult takes 7 to 20 days depending on temperature.The important thing is to spot it quickly as once it takes hold it can spread to other plants. .Once again there is a biological control you can use,a predatory mite called Phytoseiulus persimilis is available and are widely used by commercial and amateur growers.They feed on the eggs,young and adults of red spider mite but need good light and daytime temperatures of 70 degrees F or more if they are to breed faster than the pest,effective period of use is between April and September.They can achieve a complete clean up in several weeks and especialy if a second introduction is made two weeks after the first,the predator is susceptible to insecticides so biological control can only be used in conjunction with chemical control products containing plant oils or extracts. 

FUCHSIA GALL MITE

       
 
This insect is a newcomer to these shores only as recently as September 2007 when samples of infested fuchsia plants were sent to the RHS at Wisley,these came from the Fareham area and later in 2007 the mite was found in gardens in Middlesex and Kent.The concensus of opinion is it may have arrived on imported pot plants or could have been bought here on a cutting taken by a collector staying in the Channel Isles or the Brittany area of France where the mite is now widespread.It was first found in Brazil in the 1970s and has now spread to California,France,Germany and the Channel Isles so it was only a matter of time before it reached us and it was the type of pest we could have done without.The gall mites are about 0.25mm long so being microscopic they are too small to be seen without some magnifying aid,they infest the new growth at shoot tips where they feed by sucking sap,they also secrete chemicals into the plant that prevents the plants normal development.With the increase of the infestation the plant produces increasingly distorted foliage [ picture above ] until it isunable to produce normal leaves or flower buds,eventually the shoot tips produce a mass of yellowish green or reddish pink distorted tissue instead of leaves or buds.Being tiny the mite cannot travel far on its own but can be blown by the wind or hitch a ride on other insects,the mite has several generations between late spring to autumn and takes about 21 days to complete its life cycle at 64 degrees F.It cannot survive temperatures below 41 degrees F and it overwinters under bud scales but once again heated greenhouses may allow it to continue living and with winters becoming milder it might even survive outside.Cutting off the infected shoot several nodes down is only affords a temporary respite as the plant has every chance of being reinfested.          There are limited options for us amateur gardeners because gall mites are relatively tolerant of pesticides,Bifenthrin found in Scotts Bug Clear Gun,Bayer Sprayday Greenfly Killer Plus or Doff All In One Garden Pest Killer.Checking the web I have found some more but not sure about manufacturers,one is called Sevin and also Isotox Insect Killer by Ortho which are miticides also Bayer Rose Advance,Ultra Fine or other light horticultural oil sprays,also mention was made of chemical called Imidacloprid having a good result so anything with this chemical in is worth a try.Dont forget if you think you have the dreaded gall mite contact your local DEFRA office and samples of infestation can be sent in sealed polythene bags along where the plant is growing PHSI Central Science Laboratory,Sand Hutton,York Y04 1LZ.

   CAPSID BUG

       

             
 Capsid  bugs are horrible little green insects measuring about 6mm long with six long  legs and antennae,they suck sap mainlyfrom the shoot tips and buds and the young  leaves become distorted and develop tiny holes,young buds are misshapen and are killed off.As they feed they secrete a toxic saliva into the plants which kills  the cells around the feeding area,when the leaves expand from the buds the dead  areas tear into many small holes [ picture below ],the signs of damage appear from late May to September unfortunately by the time you notice it the main damage is done.      
 If  signs of damage is seen or spot a bug then you can spray with the chemical  Bifenthrin which is in Bayer Sprayday,Greenfly Killer Plus,Doff All In One  Garden Pest Killer,Bayer Bug Free or Scotts Bug Clear Gun. Because when you  see the damage it may be too late I have tried to spray the outside fuchsias  when the shoots first show with a systemic insecticide and repeated it after  four weeks,I have done this for the last three years and the damage has been  reduced dramaticaly so maybe its worth a try.

 

   
Fuchsia Rust

            

          This is a particularly nasty fungal disease that once it takes hold is very difficult to eradicate completely and in some cases it is better just to bin the plant.It thrives on lower temperatures and moisture so is more prevelant in Spring and Autumn although with this Summer being so wet it did not slow down the development It develops pale patches on the upper surfaces of the leaves and corresponding to small raised orange pustules on the lower surfaces,containing dusty orange spores.Caused by the rust fungus Pucciniastrum epilobii. Orange,then brown spores are produced on fuchsias and willowherbs. The brown spores cannot re-infect these hosts, but instead cause infections on young needles of firs. These in turn produce spores that can only infect fuchsias and willowherbs. Damage to firs may be important in forestry, but it is the fuchsia stage of the lifecycle that is likely to be noticed by gardeners.           
Rust is a serious problem for the fuchsia grower since infected plants can be badly weakened as spores restrict light from getting to the leaves thus reducing food production leading to stunted growth. The fact that rust is so highly contagious is probably its most dangerous aspect. However, good preventative measures combined with prompt controls as soon as the disease is identified, will help to reduce the rust problem and ensure healthy plants.          
Spores can be blown by the wind,fall off if you disturb the leaf,be transfered by insects or even moved to another plant by you,infected leaves need to be removed as carefully as possible as soon as they are spotted and dumped in the bin not the compost heap.Then they need to be sprayed on a fortnightly basis with a suitable fungicide,Rose Clear 3 and Rose Clear 3 gun [ myclobutanii ] Fungus Clear 2 Ultra [ triticonazole ] and Fungus Clear Gun [ myclopbutanii ] and there is an organic one called Fungus Fighter.Also it is advisable after you have removed the infected leaves to scrape compost off the top of the pot and replace with fresh compost,this will hopefully remove any spores that have fallen on to the surface.

 






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