With so much succulent growth on your young plants in spring and summer, you'll have to keep a constant check on them for outbreaks of pests and diseases, especially the troublesome trio of aphids, white fly and red spider mite.
Be vigilant at all times, check over your plants frequently, remember, prevention is better than a cure!

APHIDS come in quite a wide range of colours, though we will all be most familiar with the ordinary greenfly. These sap-sucking insects feed on tender young shoots and increase very rapidly if left unchecked. Tell-tale signs of their presence at this time of the year are leaves curled round (foliage does this in self-defence!) and a sticky secretion on the of top the foliage. When you inspect you'll find the offending culprits on the underside of the leaves just above. Later on, at the height of the flowering season the aphids prefer a change of diet and tend to go for the flowers, misshaping the buds to a sort of banana-shape.
Your finger and thumb are the best anti deterrent weapons, squash'm! However, if the sheer number of plants defeat you, you can spray with a suitable (= kills greenfly & aphids specified on the label) insecticide. Be safe, do follow the instructions and dilution rate precisely. You're likely to have to spray several times during the season and it is advisable to use a variety of makes, as otherwise the aphids can become immune to your favourite brand! I prefer to use a combined systematic spray, especially early in the season. It kills what it hits, but is also absorbed into the plant's sap and subsequently kills off any remaining aphids that take a nibble, it stays active like this for a few weeks.

WHITEFLY need no introduction, we have all be caught out by them at some stage. Often actually innocently introduced to our clean environment by bought-in plants. They have become a major problem in recent years with even the commercial growers failing to keep them in check due to their acquired immunity to the main combating chemicals.
The little moth-like white creatures are easily seen when disturbing plants as they then happily flit about before settling on another of your treasured plants. Leaves will also be noticeably sticky and can be covered in sooty mould. The young whitefly feed on the sap of the plants, then excrete sticky honeydew in considerable quantity, which in turn breeds this rather unsightly sooty mould.
On close inspection of the underside of leaves you'll also notice pinprick scales, which are the real scourge, as during spraying they often escape, being well hidden underneath and anyway immune to the insecticides available to the amateurs, it seems, and then to hatch out a few days later, to perpetuate the problem!
Again general cleanliness and starting off with clean plants in spring is vital. This can be achieved if you let your plants defoliate and rest in the traditional way during the winter. If growing on the biennial system, keeping young plants ticking over as might be, but in full foliage, you need to be extremely vigilant, inspecting your plants frequently and thoroughly. You have to destroy ever single white fly present to prevent a menacing outbreak at the onset of the warmer weather in the spring! It is also advisable to keep bought in new plants and cuttings in isolation and under close observation for a while. Best line of defence, especially in view of whitefly becoming increasingly more immune to our chemicals, is to inspect your plants frequently, paying particular attention to the underside of the foliage and to ruthlessly squash any you see immediately!
Whitefly develop tremendously quickly - they can lay their own eggs within a week of hatching out. Hence, spraying at weekly or forthnightly intervals will not solve the problem. If troubled by them you really need to spray at three day intervals, making sure you cover the undersides too, ringing the changes as to what brand you use, and to keep up this spraying repeatedly till all white fly have indeed perished.

RED SPIDER MITE is increasingly becoming a major problem now too, with the hot summers of recent years. It can easily get a damaging strong-hold before it is noticed, as they are so minute, not noticeable by the naked eye really. Often only detected when an infestation has well and truly taken hold. Newly hatched mites again feed on the plant's sap attaching themselves to the underside of the leaves, which before long mottled or even dead areas then dropping off prematurely.
In really bad cases plants can become completely defoliated and often succumb. You'll first notice you have red spider mite when plants have lost the green, healthy shine on their leaves. They become dull, somewhat greyish and of mottled appearance. Holding a leaf up to the light you can see through it where the mites have been feeding and destroyed the leaf tissue and with a magnifying glass you can also detect the minute mites amongst their webbing.
Prevention again is best, so improve growing conditions. They thrive in hot dry conditions, so aim to combat them by providing high humidity, damping down often and also ensuring you have adequate ventilation. Spraying with a suitable insecticide (= one that specifically states on the label that it kills red spider mite), might solve the problem. However, if only a few plants are infected it is much safer to be ruthless and just dispose of them immediately to avoid it spreading. CD2000