GARDEN PESTS & DISEASES N-Z
Grosafe Garden has a wide range of pesticides to assist in controlling many common pests and diseases found in New Zealand gardens. Our range (apart from Buxus Blight Fighter and GroVentive® Garden) is certified for organic input No.4547.
Please check our series of Spray Calendars for helpful information on the optimum times to apply treatment.
Psyllids cause injury to plants by feeding with piercing-sucking mouth parts. Both adults and nymphs cause injury. The nymphs inject a ‘salivary toxin’ into the plant while feeding. The signs and symptoms of psyllid include: Severe wilting, presence of honeydew secreted by nymphs, making the plants sticky and often appearing dirty, yellowing of leaf margins with upward curling of the leaves, retardation of new growth, no fruit production, or over-production of small fruit.
Rose Black Spot
Rose black spot is caused by fungus. Dark-brown to black leaf spots develop on the upper leaves, which eventually become yellow and drop. Black spot can be distinguished from other leaf spot diseases by its fringed edges and dark black colour. Raised, reddish-purple spots may also appear on rose canes. Warm, humid conditions favour its germination and growth. If left unchecked, it can cause a rose bush to totally defoliate.
Treat with EnSpray 99® Spraying Oil
Common rust is a fungal disease that attacks roses, ornimentals and lawns. It is most often found on mature plants where symptoms appear primarily on the surfaces of lower leaves. Severe infestations will deform and yellow leaves and cause leaf drop. Black spores are visible on leaves and stems in fall and overwinter inside infected stems which are distinguished by dark, corky blotches at points of infection. The spores are spread by wind or by water splashing back up onto the foliage.
Treat with Free Flo Copper
Sap-sucking pests attach themselves to the twigs, leaves, branches and fruits of host plants. Scale-damaged plants look withered and sickly. Leaves turn yellow and may drop from the plant. They may also have sticky sap or a black fungus on the leaves and stems. Heavily infested plants produce little new growth. If scale insects are not controlled, death of infested plants is possible. Scale insects are invasive and will infest other plants, so move infested plants away from healthy ones.
Small and more-or-less rounded holes are a result of plant disease infections, especially fungal leaf spots and bacterial canker. The latter attacks members of the Prunus family – such as cherries and plums, both edible and ornamental. The disease causes the part of the leaf that is affected to turn brown and die. This dead portion then falls out of the leaf leaving behind the hole. Improving the plant’s growing conditions, will reduce stress and make the plant stronger and less likely to be attacked.
Spittlebugs are known for the frothy spittle mass they produce while feeding on plants. Spittlebug nymphs pierce the plant stems and suck plant juices. In most cases, especially on annuals and perennials, spittlebug feeding is not damaging to plants. If too many spittlebugs are present, feeding can cause leaves to lose their shape.
Treat with GroVentive® Garden
Extremely active, thrips feed in large groups. They leap or fly away when disturbed. Thrips damage plants by sucking their juices. Plant leaves may turn pale, splotchy, and silvery, then die. Injured plants are twisted, discoloured and scarred.
A fungal disease which leaves scabby marks on the skin is likely to be verrucosis or citrus scab, which can affect all citrus fruit. It looks unsightly but the quality of the fruit inside is not affected. The disease doesn’t cause major problems however, it should still be treated as it negatively affects the health and vigour of the tree, making trees more susceptible to other problems.
Whitefly is a sap-sucking insect that is often found in thick crowds on the undersides of leaves. Both nymphs and adults damage plants by sucking the juices from new growth causing stunted growth, leaf yellowing and reduced yields. Plants become weak and susceptible to disease. Like aphids, whiteflies secrete honeydew, so leaves maybe sticky or covered with a black sooty mould. They are also responsible for transmitting several plant viruses.