Coping with Caterpillars – Part 2

If you’re having a tug-of-war with caterpillars over who gets a fair share of food from your edible crops, you’ll know how frustrating it can be to come off second best! As mentioned in Coping with Caterpillars – Part 1, the first step is observation and diagnosis to ‘know thine enemy’.

 

Use a magnifying glass to get up close and personal to see what's happening in your patch.

The next step is what intervention you choose to use to manage the situation.

First though, if you’re not familiar with Integrated Pest Management (IPM), this video covers the basics :

 

13 Sneaky Strategies to try:

 

  • Prevention is Better than Cure. Exclusion is a simple but effective method of keeping moth and butterfly mothers at bay. Fine mesh netting (even old net curtains), bags or sleeves, floating row covers and shade cloth stop butterfly mummies starting their families in your veggie patch ‘maternity ward’.

 

Butterfly sitting on protective crop netting

If you only have a small space or garden in containers, this is such a cheap, easy method to use. No access – no eggs are laid!

 

  • Companion Planting. I use nasturtiums, flowers and herbs to draw the attention of these mummies ready to unload their baby bundles away from the edible crops I want to protect. I’ve found this strategy to be extremely effective, although I do use it in conjunction with other techniques on this list. Nasturtiums in particular work well as a ‘catch crop’ or sacrificial plant for mummy white cabbage butterflies to lay their eggs on without destroying my food crops.

 

My healthy vegetables interplanted with strongly fragrant herbs

Another strategy I use is interplanting strongly scented plants in amongst the food crops which helps discourage the butterflies from laying nearby (sage, dill, oregano and rosemary act as decoy plants).

 

  • Plant Diversity. The more plant species you grow, the less likely for pests to attack. Each plant secretes its own unique odour or ‘signature smell’ that helps attract (or repel) butterflies and moths (as well as other insects). The more diverse your garden is, the more mixed and confusing scent signals it sends to egg-laying adult moths and butterflies and using this strategy has considerably reduced caterpillar damage in my garden. I’ve planted tall skinny spring onions, nasturtiums, basil, dill, sage and marigolds very effectively with broccoli, cabbage and cauliflower and found I had no caterpillar problems at all this year. The brassica crops were completely left alone.

 

One of my patches of nasturtiums

I planted several large patches of nasturtiums which acted as radar beacons to the mummies who happily had their babies there rather than on my valuable broccoli etc. I could afford to lose a few leaves on the nasturtiums but not the food crops. This works for me!

 

  • Confuse Them and Lose Them. Planting my veggie patch with different shaped edible plants rather than a whole patch of the same veggie is another way to confuse the butterfly and moth mummies so they find it harder to locate their food source. i.e. plant ‘diversity’. A cottage garden design helps minimise damage rather than planting in rows that all look the same. You can still design an attractive kitchen garden by repeating your plantings at regular intervals.

 

White cabbage butterflies in flight

Growing a lot of one plant together is like standing on the tarmac waving a flag at the approaching airplane as a landing beacon, beckoning them to touch down! Photo: White cabbage butterflies coming in for a landing.

 

  • Early Detection. Eggs won’t eat your plants and little caterpillar mouths eat small holes but the bigger they grow, so does their appetite and the more of your plants they consume. Just like teenagers who open the fridge constantly looking for food, a voracious army of caterpillars in your patch will seriously deplete your crop in no time unless you ‘close the fridge door’.

 

A caterpillar's handy work: skeletonised bean leaves.

Unless you have a food surplus you can afford to share or don’t mind a bowl of leaf spines in your salad, you might consider taking early action = walk your patch daily to minimise damage before it gets out of control. I learned this the hard way after catching the huge caterpillar culprit on the job … but FAR too late!

 

  • Birth control. This is a bit like playing ‘hide and seek’ as a detective in your patch. It’s a great game for kids playing the role of Pest Patroller.

 

Butterfly eggs on underside of marrow leaf

Search for eggs on the undersides of leaves and in the crown or centre (e.g. cabbages, broccoli, Asian greens and lettuce) where the tiny caterpillars will hatch.

 

  • Look for ‘clues’ like holes in your leaves and telltale green droppings (frass) to detect their location. Use a magnifying glass if you have one. Tip: If you can’t bend over easily, glue a small mirror onto the end of a long lightweight stake and position under the leaves to check the presence of suspects. Smearing a pile of tiny eggs with your finger onto the leaves is much easier and less time consuming than looking under every leaf, stem and fruit for mature culprits who are already wriggling and eating their way to veggie heaven.

 

“It is by studying little things that we attain the great art of having as little misery and as much happiness as possible.” – Samuel Johnson

 

  • Green Thumb. I often wonder where this term originated, because my take on having a ‘green thumb’ is not so much about being an experienced gardener, than using this appendage for pest management purposes and the resulting green colour that results! This simple but effective extermination system of hand removing caterpillars on the leaves where you find them has several benefits (unless you’re squeamish!)

 

Checking under leaves for culprits.

Firstly, you put an end to the problem immediately and secondly, as you squash the culprits, they release a fear pheromone which is a strong aroma easily recognisable by insects. I smear the remains all over the leaves as a warning to impending arrivals.

 

  • I think of this strategy a bit like a mum about to give birth, driving into the carpark of her local hospital where she’s been many times before (perhaps with previous births) and seeing multiple fatalities at the front entrance. If it was me, I’d turn my car around and have my baby at another hospital! So I try to send a message to the butterfly mummies that are thinking of stopping by my plant ‘nursery’ to drop off more baby bundles, to think twice and find another ward where there are less infant mortalities. So far, this seems to work well … unless it rains.

 

Chooks love any insects as a treat.

Alternatively, if you have chooks, then drop the caterpillars in a container and spoil them with a protein treat.

 

  • Nature’s Nets. I used to wipe out spider webs regularly in my patch until I realised the amazing role they play in pest management.

 

Natural pest control - spiders reduce the population of moths and other night flying insects.

One morning I snapped this spider’s web net bejewelled with dew – the perfect solution for catching night flying moths.

 

  • ‘Bed & Board’ for Birds. If you create an environment to attract birds to your garden, you’ll also find they hang around and take care of your pests – caterpillars are an easy pick for any sharp eyed bird. A diversity of trees and shrubs will provide a safe habitat for small birds to roost/nest and flowering nectar species will provide food.

 

Bird taking a bath in the garden

A bird bath in a protected place close to this habitat will enable many of your native birds to come in and do the job of pest management for you … a small investment that pays large dividends.

For every creature you have in excessive numbers, there is at least one and probably many other creatures who would be delighted to relieve you of the excess, for free! In natural systems everything, alive or dead, is food.” – Linda Woodrow, ‘The Permaculture Home Garden’

 

  • Predator Perks. You can also encourage natural enemies of pests (beneficial predator insects) to assist you. In fact, they’ll take care of pests for free, so no need for time consuming and expensive sprays and remedies.
This wasp is parasitizing infant caterpillars recently hatched out of their egg cases.

Some insects we may think of as ‘nasties’ like this wasp are actually critically important as biocontrol agents.

 

  • Some wasp species paralyse their prey (including the cabbage white butterfly caterpillars) by parasitizing (injecting their eggs) through a vulnerable body part in their unsuspecting victim as it crawls along a leaf. You can see the caterpillar below on a broccoli leaf.

 

Parasitized white cabbage caterpillar - larvae just hatched out

Here the caterpillar is totally unaware it has had strangers growing inside that have now hatched. Now this is not for the faint-hearted as it sounds rather macabre!

 

Nature's hit squad - the wasp larvae after hatching from their host.

This is a close up of nature’s ‘clean up crew’. Prior to this, when the larvae hatch out inside the caterpillar, they eat their host’s internal body tissue, saving the vital organs till the end of their meal which keeps the prey alive until the larvae have fed enough to pupate.

 

  • Tip: If you notice the caterpillars on your veggies, but they are not moving and may be a darker colour or have a papery appearance, then it’s likely your wasp ‘cavalry’ have been and gone and your pests are being dealt with nature’s way. If you think you’re up for it, watch this gory story to see the amazing way nature works in National Geographic’s video on Body Invaders.

 

  • Maintain Pest:Predator Balance. For a healthy organic garden where the pest to predator ratio is in balance, I feel it’s important not to over-react to a perceived ‘problem’. By having a small number of pests (whether they be a few caterpillars, aphids or grasshoppers), your garden will automatically attract these insect’s natural predators who are looking for a regular food source.

 

Preying Mantid with dinner

If they find their favourite foods on the menu at your place (like this Preying Mantid munching dinner) they will likely hang around and take care of them for you (and you might not even notice the beneficial insects are there).

 

  • I have realised that if you totally remove their tucker, the ‘good guys’ will starve … then if you need their assistance when you have a real pest outbreak, it may take a few days for the beneficials to notice the table is set at your place for some fine dining and come to the rescue!
  • Plant ‘Good Bug‘ Tucker. If you are committed to a non-chemical approach to your pest management, my last tip is to provide food (nectar and pollen) and habitat (a ‘bed’ to play happy families and reproduce!) for your beneficial insects to encourage them to take up residence at your place. I plant a Good Bug Mix of annual and perennial flowers and herbs to attract the good bugs to my garden so I can have plenty of happy free workers doing what they love best. Even if you haven’t got a pest ‘problem’ the goodies will be on hand for when you do! This video gives you some examples of useful plants:

 

“My advice is: consider what level of damage you can live with and if a few holey leaves won’t kill you, perhaps let nature take care of its own.”

 

I’ll include recipes for home made sprays in a future post but hope these tips help swing the balance back in your favour.

Related articles: Coping with Caterpillars – Part 1

Caterpillar & Butterfly by HikingArtist.com

I’d love to know any strategies you are using to cope with caterpillars. What challenges are you dealing with?

 

© Copyright Anne Gibson, The Micro Gardener 2010-2016 – http://www.themicrogardener.com. All rights reserved.

Comments

comments

9 Comments

  1. Victoria June 29, 2014 at 11:17 am - Reply

    Hi Anne, Bunnings sells a tool which is a small mirror on the end of a flexible coil. It is used by mechanics working on engines but can be used for a multitude of other things, such as looking on the under side of leaves as you suggest and also when cleaning an oven to see if the roof of the oven is clean. Cheers Victoria

  2. Cyd August 14, 2013 at 10:06 pm - Reply

    You have some great ideas but it seems the eggs you show and suggest rubbing out with fingers look very similar to ladybug eggs which would be helping the aphids… so maybe suggest that people are aware of which is which?

    • The Micro Gardener August 17, 2013 at 1:19 pm - Reply

      Hi Cyd

      Thanks for commenting. The pic I used to illustrate my point (the yellow eggs on the leaf) is of 28-spotted ladybird eggs (these are the leaf-eating ladies who do a lot of damage to crops like potatoes). You make a good point and I agree that it’s wise to learn to identify where possible as many of the insect visitors to our gardens to avoid inadvertently wiping out the helpers. I’m not suggesting gardeners routinely wipe out any eggs they see, as it follows on from my thoughts in Part 1 on this subject. This is Part 2 in a series on Coping with Caterpillars. In Coping with Caterpillars – Part 1, I encourage people to observe and consider whether they REALLY have a problem before taking any action. I’ve listed some links under Resources in this post to help gardeners with identifying a wide variety of insects and learning more about integrated pest management principles. All the best. Cheers, Anne

  3. Sandy April 24, 2012 at 2:12 pm - Reply

    Hi Anne,
    The little caterpillars are back. I am going to cover them with fine netting. Love your advice. Do you need to leave the netting on all day and night? The only downside is I will be unable to visually see the wonderful greenery while they grow. Upside of that is I will have veggies to eat. I have grown most things from seed. The broccoli is growing nicely so hopefully the moths and caterpillars will not get through the netting. Any tips on growing broccoli, beans and peas?

    Love your site
    Sandy

    • The Micro Gardener April 24, 2012 at 10:04 pm - Reply

      Hi Sandy
      It’s that time of year when the caterpillars will still be munching away so yes, fine exclusion netting will prevent the butterflies from laying eggs on your crops. Better to keep them net on all the time as many moths of course fly and lay their eggs at night and you will expose your much loved edibles to their new babies. At the end of the day, it’s better to harvest an abundant food crop and sacrifice the visual amenity – you can enjoy a non-edible ornamental garden for beautiful greenery!
      Broccoli is a heavy feeder whilst beans and peas are flowering crops that are not quite so greedy but my advice is to prepare your soil well first with good quality compost/organic matter/organic fertilisers (or use a potting mix like mine with the nutrients built in). Then side dress at least once during the growing season with additional compost or worm castings and fortnightly liquid feeds of seaweed/fish emulsion to keep them healthy. Mulch well and keep the moisture up to them too as they will need this to access the nutrients in the soil. Peas and beans are quick growers and you’ll need support stakes unless you grow bush beans.
      Hope this helps and thanks for your feedback – much appreciated!
      Cheers, Anne

  4. Joanna February 13, 2012 at 9:32 am - Reply

    Thank you for focusing on pest management without chemicals. I stumbled upon some of these techniques such as varied intermixed plantings and “sacrificial plants” simply because my own backyard is very small. It didn’t occur to me that planting a butterfly garden with native hosts would protect my veggies, but it did! The only dismal failure has been with broccoli due to cabbage whites. I didn’t have the heart to squish the little guys, so there was not a bit of broccoli left for the humans. I think if I grow it again I’ll try your idea of netting. And, interestingly, other brassicas I’ve grown like arugula and rapini were nibbled upon but not decimated. Enjoying your blog!

    • The Micro Gardener February 13, 2012 at 9:56 am - Reply

      Hi Joanna
      Thanks so much for sharing your experiences and glad the info is useful. It’s great to hear about what others are doing: what works and what doesn’t too.
      I rarely use any sort of homemade remedy unless I have a major problem – I try to rely on these natural methods to create a balance.
      I’ve often found doing nothing initially but observing, has saved me from interfering with nature’s own remedies with beneficial predators, especially the more I have included ‘bed and board’ for them. In a small area, I’ve found netting to be extremely effective. My tip would be to first check though that you’re not trapping any unwanted pests inside the net! Been there, done that!
      Another aspect to integrated pest management is giving your plants a ‘head start’ to grow to a point where a nibble here and there won’t be too detrimental. If that means using a cloche, netting, bag, intercropping etc., then at least it gives seedlings a fighting chance. I’ve had situations where grasshoppers have arrived en masse and had their meals in my veggie patch ‘dining room’ but not done major damage because the plant leaves were mature and large enough to cope with a few holes. They could still photosynthesize and keep up with their growth.
      Interestingly I’ve also watched butcher birds and magpies follow me to the veggie patch and watch me. If I’m squashing a bug/caterpillar, I’ll throw one in their direction to give them the heads up that there’s plenty more in the cafeteria after I leave. Now I see them regularly sitting on the fence keeping a watchful eye so I’m sure they help me out doing something they love anyway!

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