Getting Control!

In our Pests and Diseases section, you will find information on the management and control of all sorts of typical garden pests, including diseases, insects (bugs), animals, and more - everything that can threaten or damage the health of your plants, flowers, and garden.

This section is going to grow over the next few weeks so keep an eye on it and in the meantime if you have a questions don't hesitate to complete the form below and send it in to us!

PESTS

Cats
It's pretty bad when you dig in your garden only to find that it has been used as the local cat convenience. If you don’t want to go to the extent of getting your own Wheaten Terrier (I could rent out my Murphy) here are some home remedies you could try.

Defence. Make it difficult for the cats to access your garden. Surround the area with a fence that leans in the direction from which the cats will approach to stop them clambering over.

You could also use the flimsy plastic type roll up fencing as it is less stable and it will put them off as it is hard to balance on.
Another technique often seen is to fit a tight wire about 10cm above the fence and this will put them off walking along the fence.

Scare tactics. Why can you never catch them in the act? Waiting with a water pistol is only for those of you with no life. Try stringing some old CD’s together with knots in between to keep them apart and hang across your garden beds or from trees to create some flickering light. I have my doubts about the “plastic bottles half filled with water lying on their sides” a method used to deter dogs from the front verge. It didn’t seem to work with dogs so would it work with cats?

Smells. I have heard of many different scent repellents that may be worth a try. These include – citrus peel, cayenne pepper, eucalyptyus, peppermint or citronella oil, or coffee grounds.

We also have Skunk Shot, a foul smelling concoction that has a natural, non-toxic oil from the chemistry of the North American skunk.

We have also been asked for Coleus canina, a plant recommended by English gardeners. It was grown several years ago by Horrobin and Hodge and sold as “Greek Lavender” and has many common names - dogsbane, the “Pee-off” or “Poo Plant” or “Scaredy Cat” coleus. It has been renamed Plectranthus ornatus and I have tracked some down to take cuttings from. If you would like to put in an order you can do so on our web site. They will need to be planted 1 metre apart and be quite established before the smell is released.

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Caterpillars
White butterfly and solutions
At the same time we are rescuing monarch butterfly caterpillars, we are also dishing out Derris Dust and Success Naturalyte to kill the voracious white butterfly caterpillars. These feed on brassicas and the green looper caterpillars make holes in a wide range vegetable and flowering plants.

Success is an interesting pesticide introduced into New Zealand a few years ago by Yates. It is a low toxicity pesticide containing spinosad derived from naturally occurring beneficial, soil bacteria found in rum barrels in the Carribbean. It works through both contact and stomach action, for controlling both egg and caterpillar stages. It is also safe to use around beneficial insects and birds and keeping these feeding in your garden in turn keeps down other pests.

During late summera nd early autumn we also see the effects of a few of our native caterpillars that have developed a symbiotic relationship with specific plants. Although the damage is unsightly to us they will rarely do so much harm as kill the host plant. These include the following:

Cabbage Tree Moth Caterpillar
This is a small looper caterpillar either bronze or green.

They will be found in the centre spike of the cabbage tree eating holes in the young foliage which is often not obvious until that foliage matures and unfurls. Success in their control is dependent of you applying the pesticide before you notice the damage.

Kowhai Caterpillar
Also the larva stage of a native moth; quite pretty, green with black and white lumps along each side. They are hard to spot among the leaves but will very quickly strip a tree bare.

Once again, this will rarely cause long term harm and a healthy tree will recover quickly. However you may need to protect young kowhai recently planted with Derris Dust or Success.

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Roller Caterpillar

Lovely fresh and tender spring growth is a gourmet delight to leafroller caterpillar. There are several different types of leafroller caterpillar, several of them the pupae stage of native moths all cleverly rolling and tying up leaves to make a shelter. They then feed on the leaves.

Which particular caterpillar matters not and the range of host plants is wide and varied. This week I have identified them in the tightly closed new leaves of Hebe ‘Wiri Prince’ and a friend has seen the damage on her Viburnum ‘Emerald Lustre’. We frequently see the new growth of camellias eaten.

Yates Success Naturalyte will control these caterpillars and is a welcome new introduction taking the place of Orthene. The benefits of Success are:

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Fluffy Bums
Cute looking insects characterised by their white fluffy tails. They are actually teenage passion vine hoppers which are rather damaging as they suck sap from a wide range of plants.

The adults look like small moths with transparent wings. Control both stages with Confidor, a very effective and selective stomach poison for them. Other remedies include the plant based Yates Insect Gun, Nature’s Way Pyrethrum or Betta Bug Garlic and Pyrethrum Spray.

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Grass Grub Beetle

Grass Grub Beetle eggs are laid in the soil over the summer and hatch into larvae in about 2 weeks. The larvae are creamy-white and 10-20mm long and feed on the roots of turf and other plants. Infested lawn will turn yellow and die off. The dead turf can be rolled back like a carpet as all the roots have been eaten. Large numbers of starlings feeding on the lawn also indicate a heavy infestation of grass grub.

Control by sprinkling the area with Diazanon prills (Yates or Watkins Soil Insect Killer) and watering in well as per label instructions.
Potted plants that grow poorly or wilt may be infested with the larvae. These symptoms are noticeable from March to July. Drench in a solution of Confidor.

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Porina

Porina is a native moth in flight from spring through summer, damaging turf in autumn to spring. The larvae that cause the damage are greyish yellow with a dark brown head and can be up to 75mm long. Their presence is noticeable by the tunnels they leave as they emerge at night to feed on grass.

Control with Diazanon prills but do not water in, leaving on top to be injested.

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Thrip
There are 1000s species of thrips in the world and quite a few are serious plant pests. They can range in size from 0.5mm – 15 mm long and in colour from white to yellow to black.

Thrips attack the flowers, fruit and foliage of a variety of plants including rhodendrons, many vibernums (ever seen a vibernum hedge with pale grey and white mottley leaves), roses, fruit trees, azaleas, gladioli and a variety of vegetables such as tomatoes, onions and beans. Thrips lay eggs inside plant tissue and the pupae feed on plant juices and some also spread plant viruses.

Symptoms
Thrips scrape the surface of the leaves and petals, and suck the sap, leaving a white mottled appearance on leaves. Other symptoms are browning on petals and fruit, and flower drop. If left unchecked the leaves, new shoots and flowers will become deformed and stunted.

Defence. You can use Confidor to control them, and in the case of rhodos and azaleas, you can use bandgaes which are attached to the lower trunk, soaked in confidor. Neem Oil can also be used in some cases.

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Scale Insects
There are many different types of scale insects found on fruit trees and ornamentals.
Most are tiny and have hard rounded coverings.

They fix themselves to leaves and stems and suck sap. Infested plants will have leaves that turn yellow and are often covered with black sooty mould.

This is prevalent on cultivated native trees and shrubs, especially hedges. When you see sooty mould do not reach for a for a fungicide but spray with a combination of Confidor and Conqueror Oil

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Snails
Even though it is cold slugs and snails are still active and can cause much damage, especially to young seedlings that they can chew to the ground overnight. They are persistent and destructive.

Remove obvious shelter sites, damp places, long grass and weeds where they like to hide. Bare soil is usually drier and not as attractive for them to slither over.

Be careful using baits, some are extremely toxic especially to dogs.
Blitzem and Slug Slam will need to be laid every 7-10 days or after rain. Mesurol is longer lasting, has a bitter taste to deter dogs and controls slugs and snails for several weeks under all weather conditions.

Tui Quash is our preferred bait. It has been a huge breakthrough as it is a more effective control and virtually harmless to pets and wildlife. Quash is a bran-based, brown pellet to be scattered around susceptible plants. Slugs and snails find Quash highly attractive and consume the pellets in preference to your plants. Once they have eaten, they loose their appetites and head off to die – quickly and without a trace. Shells are seldom found after treatment with Quash.

The active ingredient in Quash is unaffected by temperature and humidity and works exceptionally well in the cool, damp conditions slugs and snails love.

The active ingredient (Iron EDTA Complex) is rated less toxic than common salt. It is kind to the environment, doesn’t affect earthworms or other beneficial insects and has no effect on birds or hedgehogs that eat the “Quashed” slugs and snails. The iron released into the soil from the disintegrating pellet is a valuable nutrient source.

Sharp sand or eggshell fragment laid around plants is considered by some as an organic deterrent. According to Rudd Kleinpaste this will not have any effect as “the sole of the snail’s foot is never in contact with the substrate – there’s always a layer of mucus in between”.

 

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