Whitefly

Whitefly is an important pest of protected crops. Adults usually found laying eggs on underside of the youngest leaves. Newly hatched larvae are mobile for a few hours before settling as immobile 'scales' where they suck plant sap. High numbers of whitefly produce large quantities of honeydew encouraging black sooty mould.

Type: Parasitic wasp. 

How it works: Adult wasp lays 60 - 100 eggs singly into whitefly scales, which turn black as the parasite develops. 

Species controlled: Glasshouse whitefly (Trialeurodes vaporariorum) and limited control of cotton whitefly (Bemisia tabaci). 

When to use: Encarsia are introduced as pupae either on cards, which are hung within the crop or as loose black scales. 

Rates of use:
Cool grown crops: 3 wasps per 1m2 until week 12 and then 1 wasp per 1m2 per week. 
Heated crops: 0.5 to 1 wasp per 1 m2. If whitefly are present increase rate to 5 wasps per 1 m2 for 6 weeks. 
Poinsettia: Preventative is 1 wasp per 3 plants per week; curative or where Bemisia tabaci(cotton whitefly) is suspected then 1 wasp per plant per week. 

Also available as a 50:50 mix with Eretmocerus to provide improved control of whitefly on many crops.

Type: Parasitic wasp. 

How it works: The orange/yellow coloured adult wasp lays an egg next to and slightly below a developing whitefly larva (scale). This hatches and feeds on the whitefly larva finally pupating within the empty host skin as a light yellow 'mummy'. A small hole may be found after the adult wasp has emerged from the whitefly pupa. 

Species controlled: This very useful parasitoid can attack, kill and develop in several whitefly species, including Bemisia tabaci (cotton whitefly) and Trialeurodes vaporariorum (glasshouse whitefly). 

When to use: On heated, edible and ornamental crops (+16°C) this wasp can be used throughout the year. On other crops use late spring to late autumn; ideal for poinsettia crops. 

Rates of use: 2 to 8 wasps per m2 of crop area, introduce low rate weekly or high, curative rate for a minimum of 5 to 6 weeks. Also available as a 50:50 mix with Encarsia
 to provide improved control of whitefly on many crops. 

This parasite is released under licence for use on glasshouse grown crops, please contact Fargro for further details.

Type: Predatory bug. 

How it works: Adults and nymphs attack all stages of pest. 

Species controlled: Whitefly, but will also feed on leafhopper, caterpillar, leaf miner, spider mite and most soft bodied prey.

When to use: Early season. Used mainly on tomatoes (not cherry tomatoes) and aubergines. Consult Fargro for advice. 

Rates of use: 0.5 to 1 per m2, usually as a single introduction in early season. Long generation time of six weeks means that it takes time before it exerts a significant effect on the pest populations and other controls will be necessary before it is fully established. 

This predator is released under licence for use on a limited range of glasshouse grown crops, please contact Fargro for further details.

Type: Predatory mite. 

How it works: Predates but can survive in the absence of prey feeding on pollen. 

Species controlled: Predates on whitefly (eggs and larvae), as well as thrips. It will not control established populations or where large numbers of adults are moving into the crop. Consumes more thrips per day than the standard A. cucumeris and unlike A. cucumeris will predate on second instar thrips. Populations have the potential to grow faster than A. cucumeris. 

When to use: Introduce early into the crop cycle to protect. Requires minimum temperatures of 15°C night and 20°C day. 

This predator is released under licence for use on a limited range of glasshouse grown crops, please contact Fargro for further details.

Type: Predatory mite. 

How it works: Predates and can survive in the absence of prey feeding on pollen and mould. 

Species controlled: Predates on whitefly (Trialeurodes vaporariorum and Bemisia tabaci) eggs and larvae, as well as, to a lesser extent, spider mite and thrips. It will not control established populations or where large numbers of adults are moving into the crop. 

When to use: Introduce early into the crop cycle, to protect. Requires a minimum temperature of over 18°C. Unsuitable for some crops. 

This predator is released under licence for use on glasshouse grown crops, please contact Fargro for further details.


  
  
 Encarsia adult (Photo: Holt Studios) Eretmocerus adult (Photo: Holt Studios)
  
  
  
 Macrolophus nymph (Photo: Holt Studios) Amblyseius montdorensis adults (Photo: Holt Studios)