PESTS AND DISEASES
THRIP: These tiny insects are only 1/25 of an inch long yet if left to infest they can cause a great amount of damage to your roses. Thrip have piercing mouthparts, which they use to obtain sap and water from the roses usually while still in bud form. Thrips are mobile and will crawl, jump, walk or fly to any target they focus on. Having Thrips feeding on your roses will result in dull blooms, sometimes completely deformed and usually with a bruised look around the edge of the petals. To eradicate Thrips in your garden, trim all infected flowers off the bush and spray with an insecticide such Malathion or Confidor.
APHIDS: Aphids are small, soft bodied sucking insects that feed in colonies on your roses young leaves and succulent new shoots, making them especially prevalent in Spring and Autumn. Aphids can be green, black or brown and when feeding on your roses often cause the foliage to curl and become deformed as they have literally sucked the life from your new growth. Aphids excrete a sugary waste product called honeydew, which appears like a ‘snail trail’ and does attract ants, bees and wasps. Aphids can be eradicated by the use of an insecticide such as Malathion or alternatively the Beat-a-Bug Insect spray is completely natural made from Garlic and Chilli and works a treat! New to the market is a granulated insecticide called Resolva which is very effective in preventing Aphids and Thrip infecting your roses if put down on the soil after pruning.
SPIDER MITE: Spider Mites are microscopic and cause damage by removing sap from the undersides of the leaves causing them to develop a bronze colouring. The undersides of the leaves may have a silken webbing adhered to them and the eggs appear as tiny grains of sand stuck to the leaf. As a result of the mites the pigment is drained from the foliage and often the plant will defoliate. Breeding in warm, dry places, Spider Mite is highly prevalent in late spring and summer. We recommend a miticide named KELTHANE to eradicate Spider Mite, which should be applied over the entire plant especially under the foliage. Another product that can be used and is also organic is NEEM OIL – very effective, readily available and safe!
LEAF CUTTER BEE: If you have something eating your roses by taking a perfect semi-circle from your foliage it is more than likely the Leaf Cutter Bee using your roses to build a nest. Once they have completed their nest they usually leave your roses alone and we do not recommend spraying, as it will kill the “good” bees as well. Their nest is usually found in a tree nearby or under the capping of your fence.
BLACK SPOT: Black Spot is caused by the fungus Diplocarpon rosae and tolerates a wide range of temperatures. It does need a high relative humidity and infection is greater on leaves that remain wet for six or more hours. Lower leaves are usually the first to become infected by developing the black spot, turning yellow and ultimately dropping off. Infected fallen leaves blown by the wind will disperse the fungus around your garden so raking them up will help. We recommend spraying with TRIFORINE or MANCOZEB regularly to keep black spot under control.
POWDERY MILDEW: Powdery Mildew appears as a white/grey powdery fungus growth over the foliage, stems or flowers of the infected rose. Young foliage and stems are most susceptible. Mildew usually prevails on roses that are retaining too much moisture and/or not getting enough sunlight. Leaves can also curl and become burnt on the edges when the sun becomes more intense. To eradicate powdery mildew we recommend spraying with TRIFORINE twice in 2 weeks.
RUST: yellow rust spots appear on the topsides of leaves in the cooler weather of Autumn and Spring. These infected leaves become twisted and dry and usually drop off. To control rust we recommend spraying with a fungicide such as TRIFORINE twice over a fortnight. Thinning the bush out before spraying will also help eradicate the infection.
IRON DEFICIENCY: A deficiency in iron will cause yellowing of the younger leaves and leaf veins will remain a darker green in contrast to the rest of the leaf. Iron is essential for the growth of your roses as well as disease resistance. The most common cause of Iron deficiency is a high PH (Over 6). This problem is especially prevalent in coastal or limey areas and can be corrected by the application of a soluble substance named Chelated Iron – this is also available in a liquid form (Irondex). If you live in an area with high limestone content we recommend using cow manure in September and January as well as a regular feeding of Black Magic Rose Food.
DIEBACK: If your rose stems are starting to go black at the ends and this is travelling down your stems you could have dieback. If you suspect this is happening to your roses it is important to spray with a product called Rid-a-rot twice in 3 weeks before you cut any dead pieces off the ends. Mixing seasol in with the rid-a-rot at time of spraying will improve the bushes no end. After two applications of the spray you can then safely cut off any dead ends.
When spraying weed killer in your garden be extremely careful around your roses. If your roses come in contact with weed killer, even the slightest drift is all they need, their growth will become stunted and feathery looking, which takes them on average of about two seasons to grow out of. In extreme cases the roses will never recover!
NOT SURE? CUT A PIECE OFF THAT IS INFECTED AND WE CAN ADVISE YOU IN PERSON.