2 Amazing Organic Sprays That Stop Bugs Eating Plants

by | Mar 1, 2021 | Pest, Pollinator

Many gardeners want to stop bugs eating vegetable plants. Garden pests can be devastating if you’re like me and you love vegetables, plants & trees. This article will teach you about two organic pest control products that are safe and effective for your veggie garden.

Garden Pest Control

Folks with indoor & outdoor gardens love to enjoy their connection with nature. So when our plants begin to look sad, we empathize. We negatively question our relationship with the ecosystem. Many gardeners have quit because of loss from poor soil, garden pests or disease. Neem and karanja cake are absolute miracle plant health care solutions to bugs eating plants. All garden pest managers should remember this if needed.

What Bugs Are Eating My Plants?

When I worked ecological restoration, we often planted 1,000 trees a day, or more. I loved learning native tree, shrub & herb species. I also learned disruptive weeds like Japanese knotweed, tree of heaven, scotch broom, garlic mustard, giant hogweed & Canadian thistle. This autobiographical saga begins when a low back injury forced me to change careers.

Turf & Ornamental Pest Control

So back in 2016 I became turf & ornamental manager at a Beaverton pest control company. I didn’t have a whole lot of experience with insecticides or even what bugs eat plants. But I ended up inheriting a 20th century pesticide spray program. These customers signed up in the 80’s to have their yards power sprayed with insecticide & fungicide four times a year. They wanted to keep ALL the bugs and organisms off their yard, not really knowing what that meant.

Fortunately, the 300 gallon spray truck broke down after just one or two of these terrifying treatments. It was a timely coincidence. I felt deep down pesticide sprays aren’t good for managing garden pests or keeping bugs from eating plants.

The Answer to Stopping Bugs Eating Your Plants

Shortly a twist of fate would rapidly improve my organic garden pest control insight. After all it was my job to know how to control any pathogen or bugs that are eating plants. There was much to learn about mites, moths, aphids, thrips, scales, leafminers, slugs, mealybugs, mildew, cankers, rusts, rots or spots. 

Neem & Karanja Oils

One fateful day I went to lunch with a vendor of some new products. Imported from India. Particularly products containing neem oil and karanja oil. Neem oil answered my prayers. He explained how neem oil and karanja can affect almost any plant feeding insect, nematode, and many pathogenic fungal and bacterial species. Then he elaborated how neem oil and karanja oil help fertilize and keep nitrogen ready in the soil.

Insect Repellent For Plants

Both extracted neem oil and karanja oil have proven soil assisting and plant feeding insect repelling qualities. Neem oil can be a strong insect repellent for plants. Since neem oil repels honey bees it is mostly safe for them. In general they won’t come to feed on recently sprayed or treated flowers.


Rose Midge in the Portland International Rose Gardens

We had the incredible opportunity to test the power of neem & karanja oils at the Portland International Rose Gardens. The issue was a tiny, almost invisible fly like pest called Rose midge. A typical rose midge life cycle is:

  • Adults are weak flyers which emerge from the soil in the spring and land close by.
  • Then they lay their eggs inside a newly forming rose bud.
  • Larvae then eat the yummy fresh growth of the inner rose flower while it is developing.
  • This will cause it to rot before it can bloom.

Portland Rose Tourism

At the Portland International Rose Garden this is a major issue. Master gardeners have cultivated varieties of roses there for a century. Horticulture enthusiasts travel from every stretch of the globe to bask in the rose garden’s splendor. Rose tourism in Portland is particularly busy in late June through August. 

Splendid view of City of Portland International Rose Gardens. Attribution to Jessicacu, Public domain, via Wikimedia Commons.

Our Best Rose Garden Pest Control Techniques

We developed a complete integrated organic plant health program and pest management strategy. It was aggressive.

  • We treated the foliage for rose midge & other bugs eating plants every five days,
  • Then we drenched the root zone with a neem based product.
  • We amended soil with kelp, malted barley, oyster shell, alfalfa, basalt rock dust, top quality vermicompost and mulch,
  • Applied humic acid to foliage to boost nutrient absorption,
  • And added liquid silica to create strong plant cell walls.

Organic Integrated Pest Management Success Story

By the end of the season, our organic IPM test plots showed 99% control. Nearby plots showed significantly greater rose midge damage. Interestingly those plots had already been treated with potent pesticides in the neonicotinoid class.

Still about half of the flowers were rotten, damaged from rose midge insect damage. Reactive treatments of neem oil on plots already infected with rose midge showed significantly less rotten rose buds.

What’s the Catch?

Sure, weekly applications were more time consuming than one granular spread of imidacloprid. But this was a labor of love. I thought, are pesticides really more profitable if they don’t produce safe results? Results are the value of which I believe the number on the tag is priceless.

Conventional vs. Organic

We gardeners have a challenge. When our garden, trees & landscape health is failing and pests and bugs are eating plants, what do we do? Horticulture consultants and plant nursery professionals are often quick to recommend various fertilizers or pesticides. Too often we buy a product that turns out not to be the right solution. Then you’re stuck with a full bottle of some chemical or fertilizer you don’t necessarily need.

All Natural Pesticides & Fertilizers

Increasingly many organic gardeners are starting to leave even the all natural fertilizer & pesticide bottles on the store shelf. Bio-dynamic, regenerative, no-till organic ideologies are gaining popularity among organic food producers. Organic integrated pest managers are growing stronger, healthier & more productive plants. All that with an infinitely higher level of environmental safety than what we might call conventional agriculture practices. 

Neem Oil and Karanja Oil

Sadly it doesn’t repel rats and squirrels… or slugs. But if you have bugs or just about anything else eating your plant, consider trying neem or karanja cake. You can easily mix neem and karanja as a amendment into your raised garden beds, plant pots or planters. Conversely, sprinkle on top of your garden soil as a top dress to the root zone.

How Often Can I Apply Neem Oil?

Use appropriate neem oil products about once a week for a month or two before the plant starts flowering. Very important: stop the neem applications at least two weeks before you suspect the earliest day your first flowering plant may blossom. This step will prevent any hazards of applying neem or karanja oil to honey bees and pollinators.

Where Does Neem Oil Come From?

Azadirachta indica, or Neem is a tree native to the Indian subcontinent. It’s basically Mother Earth’s secret alien technology. If you’ve ever worried about how to reduce spider mites, root aphids, thrips, white flies, weevils, mealybugs, moths, fungus gnats, leafminers, scales, nematodes, and even pathogen fungi and other disease-causing microbes, take a deep breath.

Azadirachtin as an All Natural Insecticide

Azadirachtin, the most active compound in neem can actually be sucked up and transported through the plant. This and many other natural chemicals in neem can make ANY plant feeding insect unable to feed or reproduce. It’s also a strong all natural insect repellent for plants.

Although neem and karanja cake & oils may repel pollinators like honey bees when initially applied. Beware, it may be harmful if honey bees come back a week later. Plants transport azadirachtin systemically into the newly produced flower pollen. If applied improperly you may create a hazard for honey bees or other pollinators.

Is Neem Oil Safe For Pollinators?

Effective concentrations don’t last much longer than a few days to two weeks. Of course depending on the size of the plant and the environmental conditions.

With well timed, pre bloom applications, you’ll take care of a lot of early opportunist plant feeders. Check out this article from Oregon State University about pesticide safety around pollinators like honey bees.

How To Use Neem Oil Safely Around Honey Bees

If you apply neem oil, neem cake or karanja then hold off well before the plant flowers.

  • Anticipate and write down when the earliest nearby plant to your garden will produce flower blossoms.
  • Count back two weeks from then.
  • That is the latest day you should apply neem oil, neem cake, or karanja products to your garden for pollinator safety.

After flowers have bloomed and gone to seed, you can restart neem oil or cake treatments for garden vegetables, shrubs and trees. Although I’ve heard that if you apply too close to harvest you can get a richer, earthier flavor from your fruits, herbs or veggies.

Neem Oil for Indoor Plants

For indoor plants and veggie starts, neem is strongly recommended to keep fungus gnats, fruit flies and other bad guys away. Neem also has lots of other good benefits in the soil like reducing nitrification, improving structure and increasing soil fertility. 

What is Karanja Oil?

Karanja aka Pongame is a leguminous plant also native to India with properties strikingly similar to neem. It inhibits nitrification, can have active properties against plant pests and diseases and is traditionally used for medicinal purposes.

What is Karanja Seed Cake?

Sometimes organic farmers refer to crushed karanja or pongame seed hulls as “cake.” Neem and karanja cake make a great soil amendment in a 70/30 or 50/50 blend. Sprinkle karanja cake around the drip-line of your garden & perennial plants. Simply water in or mixed into the soil. You’ll notice the incredible synergistic results. This garden pest control boost will push vegetables, fruit trees, turfgrass, even shrubs & trees through the most intense plant feeding insect and pathogen pressures without using insecticide.

Neem Oil Prevents Bugs Eating Plants

If you’ve ever had plant feeding insects snack down on your precious plant babies, you’ll appreciate the power of neem oil and karanja. And you’ll thoroughly enjoy witnessing the incredible results. Always remember to keep neem oil sprays away from plants two weeks before flowering until the flowers transition to fruits. This double checks safety for honey bees and insect pollinators.

Choose Neem Cake

Granular neem cake is handy for this because you wont worry about a sudden gust of wind taking spray drift onto your wildflowers or flowering vegetables nearby.

Neem Oil Pesticides

Important Note: Neem oil and karanja can have properties that may have active effects on plant feeding insects, mites, pathogenic fungi and nematodes. However there are only a few EPA registered neem insecticides, fungicides, acaricides or nematicides. Distributors, salespersons, retailers and service specialists may not advertise non-EPA registered neem or karanja products as an insecticide, fungicide, miticide or nematicide.

Try Neem For Yourself

Don’t let this deter you. Have fun messing with neem cake as a soil amendment in the spring. Always consider the concert of organisms when making decisions about pest management out in the garden. If you’re unsure or have safety concerns, never hesitate to call the experienced professionals for Portland landscape & garden care specialist services.


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