Tag Archives: Chemicals

The 6 main pest and diseases of rose & how to treat them.

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Pest  and  Disease  Control  of  Roses  

Introduction  – What  is  IPC  and  its  Methods

For  those  that  have  followed  My  blog on

general  pest  &  disease  control   Will   remember  that    I  use  the  IPC  method  on  all  plants  especially  roses. So  you    will  just  need  to  skip  this  paragraph   until  you  get  to  the  one  you  that  you  know. For  those  that  are new .  I  will  briefly  explain  what  IPC  is  before  going  on to  the  Pest  and  Disease  section .

Briefly  I  P C  stands  for  :-

  • Identify  –  By  Identifying  the  pest  or  disease  you can  then  isolate  it  and   treat  it  without  harming  any  other  insects  or  predators  that  are  beneficial  to  the  plant
  • Prevention  –

Prevention  is  better  than  cure

If  you  followed  the  guide  lines  that  i  told you. You are   less  more  than  likely  to  get    infected by  a  blight  or  pest  but   like  the  common  cold  no  matter  how  much  we  keep  healthy  we  still  get  it.  so  is  very  much  like plants

in  their  case  they  will  become  less  sickly  if  we  observed  their  requirement  from  the  off  set  as  I   have  pin  pointed  in  the  first  blog  

Control   or  Monitor   methods –   And  finally  Control    With  the  pest  or  Disease on  rose    isolated  we  can  begin  the  applying  the  safe  practise  of  control   whether its  Chemical  or  Organic  or  mechanical

The 6 main pest  &  Diseases 

& How  to  treat them

The  main  6   pest  &  Diseases  of  roses  are :-

  1. Aphids  
  2. Black Fly
  3. White  Fly
  4. Mildew
  5. Rust
  6. Black Spot

There  are  others  pest  like  the  leaf  cutting  bee   thrips &saw flies   but  those  are  the  main  six

Saw  Flies

These are caterpillar-like larvae, which feed on the leaves of your roses in the spring. They are about 1 ¼ inch long and are light green, some with black spots. If you get on top of this pest right away, you should be able to control them by simply hand-picking them. Look for them on the undersides of the leaves.

Saw  Fly  symptoms

Saw fly larvae symptoms

These  you  just  simply  remove  and  incinerate as  the  caterpillar is  well  protected




Leaf  Cutting  bees

leaf  cutting  bee

Tel tail of leaf cutting bees







Thrips are tiny, slender, dark brown or black, sucking insects that damage and destroy opening rose buds turning them brown and leaving them only partially opened. They also feed on the upper surface of the leaf. They can be difficult to see outdoors. If you think that your rose may have thrips, take a cutting inside and shake it over white paper to see if any fall out. Look for a brownish black insect with a narrow body up to 1/16 inch long. They thrive in hot, dry conditions. Regularly watering your roses and spraying with an insecticide or simply cutting off the affected rose or leaf should do the job







  1. I have   already  been  mentioned  in detail along  with  white  fly  in  the  following  blog
  2. BlackFly  


Black  Fly

Black Fly

As  you  can  see  from  this  picture  these  pest  can  be  easily  Identified &  tend  to  swarm  in  colonies  attacking  anything  that  is  green  and  sappy  whether  it  your  green  beans or  bedding  plants  to  roses  that  have  been  over  feed  with  high  nitrogen  fertilizer  to  produce  sappy  growth .


The  best  way  to  prevent  your  roses  being  attacked  by  these  pest  is  to  carefully  check  your  feeding  of  roses.

As  I  said  above  these  and  other  pest  like  aphids  like  green  sappy  growth  for  their  piecing and  sucking  mouth  parts

Feeding this way causes problems for the plant: aphids can transmit plant viruses, and the sticky honeydew they exude can attract sooty moulds to grow

As  in the  case of  lime  trees  every    where

Good  hygiene  too   don’t  compost  any  infected  plants  in  winter  as  the  females  lays  its  eggs  in  the  autumn on  plants  to  feed  its  nurseries and  ounce  the  eggs  has  hatched  in  spring  they  fly  off   on to  much  better  food  supply  and the  circle  begins.

So by  either  bagging  up  infected  plants  or  burning  them  you  are  at  least  cutting  down  on  the  numbers  in  your  garden . But  since  they  can  fly  doesn’t  really  guarantee  you  that  you  are  free  them

So  we  go  to  the  next  Section

Control  or  Management 

There  are   3   methods  of  control

  1. Cultural  

By  this  mean   good  hygiene  and  feeding  regime  as  I  said  above  also  to  encourage  their  natural  predators  into  the  garden   like  Ladybirds lacewings   even  small  birds  feed  on  the  insects  now  and  again

Click to tweet   how   you  can  attract  more  predators into  your  garden  

Spraying  with  tar  oil  or  winter  washes   tends  to  work  well in  winter    when  the  female  lays  it  eggs

Natural  Predators

2. Biological  Control  

is comparatively expensive, but effective – if you can create the right conditions. The main problem being that there will be a time lag between being able to source the biological control of Blackfly. Together with this, there will need to be enough Blackfly for the biological predators to act upon.

However  ongoing  research according  to  this  article  here  published  in  2005

This discovery has applications for pest management – the aphid sucrase enzyme could be a suitable target for specific inhibitors that would abolish its dual role in osmoregulation and carbon nutrition of the aphid.

that  these  pest  can  be  controlled  by  spraying  or  other  methods  not  yet  mentioned,

Current research is focussing on determining the mechanism – it’s possible that an anti-microbial with the symbiotic bacteria as the primary target may have evolved in certain plants.

As  I  already  have  gone  into  detail  about  the  use  of  chemical  as  a  method  of  culture  I  wont  go  into  detail  here  but  only  to  stress  the  dangers 



The effect of Mildrew on roses

As you  can  see  from  the  picture  that  Mildew  can  be  easily  recognised  by  its  powdery  white  effect  on  leafs  and  stems .                        In  fact  Mildews  a  fungal  Disease  rather  like BlackSpot  but  cause  its  feeds  on  moisture  on  the  plant  leaves   it  easily  remedied  by  following  the  procedure


Cultural  control

If you  seen  any signs  on   your  roses  whether  on the  leaves  or  buds  its  best  to   prune  them  out  to  avoid  the  spores  from  spreading  any  further.

Good  hygiene  again  is  important  –  keep  the  center  clear  of  branches  in  the  spring  to  allow  air  flow  through  and  around  the  plant

Try  avoid  watering  from  above  or  in  between  the    branches  water  from  the  bellow ,

Avoid  watering  in  them  evening   go  for   in  the  morning    where  if  you  have  splashed  the  leaves  the  water  has  a  chance  to  dry  off

Plant  rose  far  enough  part  so  they  can  spread  out



Rose Rust


As  you  can  see  from  these  two  examples  that  rose  rust  can  be  easily  recognised  by  its  orange  flex on leaves  and buds

Rose  Rust

Rose Rust on buds

Rose  Rust

Rose Rust on leaves






And  like  Powdery  Mildew  its  a  fungal  disease  on  the  roses  but  less  severe. That  occurs  from  the  beginning  of  spring  right  up  to  summer  should  the  environmental conditions  be  right  for  the  spores  to  spread


6  Cultural  Methods of  controlling  rust  

  • Good  Hygiene  as  always  –
  1.  remove  infected    leaves  and  incinerate  to  prevent  the  spores  from  spreading    like  Black Spot   spores lay  dormant  in  the  on  the  soil  surface  until  they  are  either  splashed  up  by  the  rain  or  watering  from  above   or  carried  up  by  insects  especially  ants . So  clearing  the  ground  of  debris  around  the  plant  is  a  must.
  2. Pruning –  By  leaving  the  center  clean  and  cutting  out  crossing  branches  improves  the  air  circulation  around  the  plant  thus  reducing  the  breeding  grounds  for  the  spores  to  live  by  drying  out  the  leaves  and  buds.
  3. Weeding  –  By  clearing  any  weeds  around  the  plant  esp  oxalis  that  get  infected  by  rust  you  are  reducing  the  risk  of  it  spreading  to  the  roses
  4. Improve  the  soil  structure  of  the  soil  by  forking  over  the  ground  in  spring  to  improve  drainage
  5. Avoid  watering    from  above   always  water  from  the  base  of  the  plant
  6. Avoid  working  on  rose  beds  when its  wet  as  you  can  spread  the  spores  by  simply  walking  around .


Chemical  Control  

When  you  see  the  first  signs  of  rust    spray   the  entire  rose  bush  with  a  copper formulated  compound   examples  can  be  found  here     until  the  bush  is  cleared  giving  it  a  good  drench.

Always    go  by  the  rules  i have mentioned   for  proper  chemical  Management

Organic  Control

There  are  many  new  ‘organic  formulations’  on  the  market  you  could  try if  you are  organically  minded  one  is  the

Disease  spray

Vitax organic spray for pest and disease


Vitax  2  in  1  pest  and  disease  control  spray    Yet I  haven’t  had  the chance  to test  it  out  yet.

But  Vitax  is  reputable  firm  that  specialize  in Rose  Care  products







Black Spot.


Black Spot  spores  on  roses

Black Spot spores on roses

Finally  I  come  to  most  dreaded  killer  of  all  roses,

Black Spot  –  as  You  can  see  by  this  image    this  too  easily  recognized  by  it  instinctive black splotches  that  are  actually   spores .  The  thin  white  threads  are  in  the  roses  stem. hence once  you  see it  its  pretty  much  that  there is  no  real  cure  for  it  except  to  either  live  with it  or  destroy  the  bush  all  together.

In  cases  of  My  many  Clients  they  rather  live  with  it  until  it  dies  completely

So  what  can  be  done  to prevent  it


Cultural  Prevention

  • As  I  mentioned  at  the  very  start  of  the  Blogs  on  roses    That  when  planting  a  new  rows  always  make  sure  the  rose  gets  a  good  start
  • Mulching  around  the  roses  in  spring  with  sterilized compost  like  Cocopeat  or  peat based formulations     This  will  stop  any    fungal  spores  that  i  mentioned  above  from  splashing  up  and  infecting  younger  shoots
  • Pruning  out  any  dead  diseased  or  dying  branches  and  incinerating  it  (  Do  not  compost  them
  • Improve  the  air  circulation  around  &  inside  the  bush  by  cleaning  out  any  inward  pointing  branches
  • Don’t  plant  roses  close  together  as  one  rose  can  spread  the  disease  to  another  and  this  too  allows  air  to  circulate
  • Water  from  the  base  only

Chemical  Control  

Organic  Control

Chemical Management

English: A sign warning about pesticide exposure.

English: A sign warning about pesticide exposure. (Photo credit: Wikipedia)

An Health and  Saftey  Warning

User habits surveys for 2007 and 2010 indicate that gardeners don’t always use, store and dispose of pesticides correctly. If you use pesticides, you are responsible for using these chemicals correctly and effectively. We must keep our gardens and allotments safe for children, pets and wildlife.


When I  was  working  for  Lambeth Council  back  in 1980  all  the  employers  had  to  pass  a  strict  pesticide course  lasting  a  year  this  was  a  tough  course    but  it  made  you  aware  of  the  dangers  of  the  product  and  how  to  safety  apply  it.

But  looking  on  the  prospective  of  the  member  of  the  public  these  rules  no  longer  apply  as most  products  you  buy  claim  to  safe  to  the  environment if  you  follow  the  instructions  to  letter

But  with  this  scare  of  slugs  pellets  and  weed  killer  getting  into  our  water  I  don’t  think  the  news  is  getting  across

So  I’ll tell  you  how  to  apply  herbicides  or  pesticides  safely

  • Read  the  Label  (  I  know  it  obvious  &  that  you  think  you  know  it  all  but  you  don’t)  How  many  of  you  put  weed killer  down   then double  dose  the  plant  again . This  is  all  wrong  the  formulation  is  worked  out  in  the  lab.  for  maximum  effect  and    by  double  dosing  you  are  probably  increasing  the  salinity  of  the  soil.
    description of  pesticide  label

    description of pesticide label


  • Calibrate  –  What  I  do if  using  a  sprayer is to  fill  up  the  water  with  water  and  go  over  the  plant   or   ground  first   making  sure  that  plant  is  soaked  ie  beginning dripping  or  that  ground   is  covered  with  spray .

I  then  see  how  much  water  i  used  and  then  do  a  simple  division  to  find  out  how  much  chemical  i  actually  use  use all  the  instructions  say  4 cap  full  to   1 litre  or  1  gallon  of  water

  • When  using  any  chemical  always  use  PVC  gloves   these  are  cheap  and  better  than  latex  gloves  that  can  rip  and  allow   the  chemical  to  get  in  touch  with  your  skin
Red  Pvc  gloves

Red Pvc gloves

Note  the  tight  cuffs  around  the  wrist  this  makes  sure  that  nn  drips  get  on  to  your  hands

  • When    mixing  the  chemical  put  in  the   some  water  first    then  add your  chemical ( Some  products  have  it  all  ready  made  up  if  so  skip this  )  and  keep  on  stirring  it  until  it  dissolves then  top  up with  the  rest  of  water  mixing  it  again .By  doing  this   you  have dissolved  and  mixed  up  all  the  chemicals
  • If  the there  a  slight  breeze  or  wind  blowing  either  wear  a  mask  or  try  not  to  spray  into  the  wind .(  Note  chemical  spray  can  carry  in  the  wind  for  miles  without  you  knowing  and  with  out  a  mask  you  likely  to  get  some  on  your  mouth   )
  • Although  there  are  organic  or  biodegradable products  that  claim there  are  safe  I  always  veer on  the  side  of  caution

How  to  calibrate  your  sprayer 

The single most asked question in pesticide application is: “How much do I put in a knapsack?”

The answer is that it depends on the calibration of your sprayer. In short, how many square metres one sprayer full of water + pesticide will cover.

It is important that the correct amount of pesticide is applied per square metre, the amount of water much less so.

An  Professional Knapsack sprayer

An Professional Knapsack sprayer

As every sprayer has a different capacity, different nozzles with higher or lower output, a different operator who works at a different speed and pumps at a higher or lower pressure, calibration is the only answer. Here is one simple way to do it:

1. Measure exactly one litre of water into an empty sprayer and prepare it for spraying.

2. On a dry hard surface where you can see the spray wet it, walk forward, continually spraying as you would normally operate until the sprayer is empty. Measure how many square metres you have covered. Let us assume that this might be for instance, 20 square metres.

3. If your sprayer is a 15 litre model you multiply its normal capacity (15) x 20 (area one litre covered) = 300 square metres. This is the area that a whole knapsack will treat.

4. To work out how much pesticide to measure into the sprayer is now very easy. Look at the application rate on the product label.

eg. Roundup ProBiactive is 5L (=5,000ml) per Hectare (10,000 sq. metres)

5. To calculate how much to measure into your sprayer:

For example: 300 (Area that one sprayer full will cover) x 5,000 (Pesticide application rate per hectare in millilitres) / 10,000 (One hectare in square metres) = 150 millilitres

amateur sprayer

Start  your  spraying

  1. Working  up  and  down  the  plant   making  sure  that  both  surfaces  of  the  leaves  are  well  coated  and  started  to  drip
  • Always  spray  first  thing  in  the  morning  this  is done for several reasons ;-
  •   to  avoid  any  harm  to  the  pollinating  insects
  • and  also  the  leaves    spores  will  be  fully  opened
  • The  plant  has  time  to  recover   after  the  spray    and  the  leaves  will  be  dry
  1. Avoid  spraying  any  chemicals  near  water

For  Weed  Killer   there  is  one  simple  rule  DO NOT  SPRAY  NEAR  WATER  SURFACES

If  you  miscalculated  and  still  have  some  chemical  left  NEVER  EMPTY  IT  DOWN  THE  DRAIN

Storing  Chemicals 

  • After you have used a pesticide, make sure that the packaging is tightly closed or sealed to avoid spillage.
  • Store pesticides in a safe place, out of reach of children and pets.
  • Take particular care to store slug pellets safely to avoid accidental poisoning of children and pets – particularly dogs.
  • Garden sheds and greenhouses are not ideal for storing pesticides as they can get very hot in summer or cold in winter. Pesticide products are best stored at an even temperature.
  • If you store it carefully, any remaining pesticide will be effective for some years to come. You can check whether it is still legal to use by using  there  database

Concentrated pesticides that have been diluted and stored may not work as well when you next use them. It is also illegal to store pesticides that are unlabelled and not in their original container for safety reasons. Remember to only dilute enough for that day’s use.

Disposing  of  Chemicals

  • Whether you’ve diluted it or not, never pour pesticides down a drain or any other water drainage system (e.g. sink or toilet) because of the risk of contaminating water and harming wildlife. You could face prosecution.
  • Pesticide containers that have held concentrated product (i.e. requiring dilution before use) should be rinsed three times adding the washings to the final spray solution. The empty container can then be placed in household waste.
  • Empty pesticide containers that have held Ready-to-Use product (i.e. trigger sprays) can be disposed of directly into your household waste.
  • Other empty pesticide containers e.g. bags and cardboard boxes can also be disposed of in your household waste.
  • Check the label for any other advice on disposal of the product or empty container.