Copyright 2013 Nick Sakovich. All rights reserved.

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2 Copyright 2013 Nick Sakovich All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means without written permission from the author. First Edition Published by: The Larry Czerwonka Company Printed in the United States of America ISBN: ISBN-13: The entries in this book are based on articles Nick Sakovich has written for a weekly gardening column in the Hawaii Tribune-Herald hawaiitribune-herald.com

3 I would like to dedicate Ask the Garden Guy to my mother and father for instilling in me the value of an education. I would like to thank my wife Ruth for all her hard work in assisting me in this book.

4 TABLE of CONTENTS Introduction About The Author i ii Part One: Plants 1 Citrus The Citrus Tree Switch : Sweet to Sour 2 Grapefruit Melanose 2 Citrus Leafminer 3 What Factors Determine Sweetness in Citrus Fruit? First Year Citrus Fruit Remove it or Not? 4 4 Dry, Flavorless Citrus? 5 Citrus Scab Disease 6 Citrus Gummosis 7 Citrus Pruning 8 Fruits, Nuts and Berries Lychee 9 Banana Fertilization 9 Avocados: Lots of Bloom, Little Fruit Bananas A Fruit for All Reasons Tropical Favorites 11 Growing Currants 12 Growing Persimmons in Hawai`i 13 Low Yield in Dragon Fruit 13

5 TABLE of CONTENTS Popolo: An Important Medicinal Plant 14 Seeds in Pineapples? 15 Papaya Fruit Shapes 15 Macadamia Nut Tree 16 Jaboticaba 16 Blueberries 17 Growing the Hawaiian Ohelo Berry 18 Cracked Mangoes 19 Small Fruit Size 19 Cinnamon: Barking Up the Right Tree 20 The Pineapple Flower 20 Cashew Trees 21 Houseplants Are Poinsettias Poisonous? 22 Perils of Watering Houseplants 23 Controlling Pests on Houseplants 23 Watering Houseplants 24 Benefits of Houseplants 25 Ornamentals Ohia lehua 26 Kamani Trees 26 Beautiful Bamboos 27 Albizia Beautiful tree or a true menace? 28

6 TABLE of CONTENTS Vegetables Spinach by Any Other Name? 29 Determinate vs Indeterminate Tomatoes 30 Portuguese Kale 30 Why Squash Plants Produce Lots of Bloom But Little Fruit 31 Asparagus 31 Growing Your Own Tea 32 Planting Bulb Onions 33 Air Potatoes 33 What is Chinese Spinach? 34 When to Pick Taro 35 Corn: So Few Kernels on the Cob? When to Pick? 35 Basil a Great Aromatic Herb 36 Planting Cool Season Vegetables Part Two: Pests and Their Management Diseases Poinsettia Scab Disease 40 Bell Peppers Rotting on the Vine 40 Plumeria Rust Disease 41 Diseases of Lettuce 42 Powdery Mildew 43 Tomatoes: Yellow Shoulder Disorder 43

7 TABLE of CONTENTS Blossom End Rot of Tomatoes 44 Ohia Rust 44 Mushrooms in the Lawn 45 Why Leaves Turn Yellow 46 Mango Anthracnose 47 Insects, Mites and Spiders Lychee Mite 48 Spiders: Friend or Foe? 48 Crab Spiders 49 Hibiscus Mite 49 Moss, Algae and Lichens Lichens 50 Moss and Lichens on Sidewalks 50 Other Pests The Gecko 51 Rats 51 Slugs and Snails 53 Pest Management Diatomaceous Earth, An Organic Insecticide Myths and Facts of Companion Planting Bt An Effective, Organic Pesticide Organic Insecticides 56 Use Pesticides Wisely 57 Using Soap to Kill Insects 58

8 TABLE of CONTENTS Integrated Pest Management A New Approach 58 Weeds Preemergent Herbicides 59 How to Control Those Pesky Weeds 60 Invader in the Lawn 61 Biological Control of Weeds 62 Part Three: Garden Activities 63 Fertilization/Nutrition Problems with Acidic Soils: Lime Can Work Wonders 64 What does N-P-K mean? 65 Beware: Fertilizers Can Burn Plants 66 Propagation Heirloom and Hybrid Seeds 67 Planting Avocado Seeds: Will the Trees Produce Good Fruit? 67 Propagating Surinam Cherry 68 Propagation of Areca Palms 68 What is a Cocktail Tree? 69 Reasons Why Vegetable Seeds Do Not Germinate 69 Propagating Pineapple 70

9 TABLE of CONTENTS Compost and Mulch Don t Pile Mulch Against Tree Trunks 71 Mulch 71 What s So Hot About Manure? 72 What s Crawling in the Compost Pile? 73

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11 Introduction My goal in producing this book is basically what I have been doing all my professional life sharing science based information to anyone who wants to learn. There are many gardening books and websites. Many are based on opinion and experience. These two characteristics are good, but even better when backed by scientific research. In this book, I share information that has been substantiated by scientific research. If it is my opinion, I will simply say so, but you won t find much of that. The information I convey is either based on research I have conducted or am familiar with or information which I have gathered from various university websites. This material is mostly applicable to the tropical and subtropical world. World map of the tropical zone highlighted in light red and subtropical zone highlighted in purple. i

12 About the Author: Nick Sakovich is Professor Emeritus from the University of California (UC) Cooperative Extension where he held the position of Citrus and Avocado Farm Advisor in Orange County, California and later in Ventura County as Citrus Advisor. During his tenure, Nick was also Administrator for the UC Master Gardener Program in Ventura and Santa Barbara Counties. As Farm Advisor, Nick s primary focus was research and education serving the commercial growers of the county. While conducting research in sub-tropical agriculture, he directed seminars and conferences and taught various courses. His writings are published in professional journals, trade magazines and newsletters. After 25 years with UC, Nick retired in Hilo, Hawai`i and joined the University of Hawai`i Master Gardener Program. Since 2008, his weekly gardening column in the Hawaii Tribune-Herald has been highly acclaimed by his readership. The entries in this book, as well as on the website, gardenguyhawaii.com, are based on those articles. On occasion, Nick teaches horticultural classes through the University of Hawai`i Continuing Education Department. ii

13 Part One Plants Citrus 2 Fruits, Nuts and Berries 9 Ornamentals 26 Vegetables 29 Houseplants 22 1

14 1 Plants The Citrus Tree Switch : Sweet to Sour How does an orange tree produce sweet oranges for many years and then yield a crop of sour fruit? All commercial citrus trees are budded. A budded tree is like a grafted tree, except a single bud is used instead of a graft. The trunk of a budded citrus tree usually produces a slight to obvious bulge where the original budding took place; it is called the bud-union. Everything above the bud-union grew from that original bud, everything below is of the original rootstock seedling. Sometimes shoots, originating from below the bud-union, will grow up into the tree. They are generally quite vigorous and may be covered with large thorns. If the shoots are not pruned out, they will continue to grow, branch and eventually form a good part of the tree. In time they will blossom and produce fruit. This fruit is different from the variety originally purchased, and most often is quite sour. These branches must be cut out so that the original budded variety can repopulate the tree and produce sweet fruit. In areas where frost occurs, the original budded portion of the tree may be killed due to cold weather. Often the rootstock survives and will put forth new shoots. These shoots of course will produce the inferior sour fruit. Grapefruit Melanose What causes the brown streaks or speckles on the skin of grapefruit? The staining is a fungal disease known as melanose. This disease displays a very interesting pattern on the fruit called tear staining. It is caused when dew, contaminated with spores, runs down over the surface of the fruit. As this happens, the fungal spores can stick to the skin of the fruit. These spores germinate and cause tiny spots on the fruit in the pattern of the water running down the fruit, hence the name tear staining. With an abundance of rain, the spores splash to nearby leaves and twigs, causing leaf drop and twig dieback. Many of the dead twigs seen in citrus trees are caused by this fungus. (Note: In high numbers, scale insects can also cause twig dieback.) Although a tedious job, it is best to prune out the dead twigs, they are store houses of fungal spores. Whether pruned or not, the trees will not die from melanose. Unless the disease becomes unusually severe, melanose is considered a cosmetic problem and in commercial operations will cause a downgrading of the fresh fruit. For the homeowner, the fruit is just as good inside as any perfect looking piece of fruit at the supermarket. 2

15 Citrus Citrus Leafminer What is happening to the citrus leaves? They look like something is tunneling through them? The tunneling damage is caused by the citrus leafminer, Phyllocnistis citrella. It is not the same one that attacks tomatoes, cabbage and ornamentals like chrysanthemums. It is relatively new to the Hawaiian Islands. It was first noticed on Oahu in 2000 and now infests all the islands. The citrus leafminer is a tiny ½ inch silvery moth with a black spot at the tip of each wing. It is the larval stage which lives inside young terminal leaves, feeding as they meander throughout the leaf. The moths are attracted to the new growth and once the leaves harden, the larvae will not be able to travel within the leaves. At the same time this pest came to Hawai`i, a tiny parasitic wasp came along with it. Because of the presence of this wasp, citrus leafminer damage has been minimized. When the leafminer is present, avoid excessive pruning which stimulates new flushes of growth. Even if the new flush of growth on mature trees is heavily damaged and looks unsightly, the yields of most citrus varieties will be unaffected. 3

16 1 Plants What Factors Determine Sweetness in Citrus Fruit? The accumulation of heat units is most important in determining the sugar content of the fruit. Simply put, citrus fruit become sweeter the longer they remain on the tree (to a point). If you think the fruit is ready to pick but find that it s not sweet enough, leave it on the tree a little longer; it should sweeten up. And what if it doesn t increase in sweetness? Of the hundreds of citrus varieties, not all are adapted to one specific area. For a given region, some varieties just won t produce good quality fruit. First Year Citrus Fruit Remove it or Not? This question comes up often in regards to young citrus trees. The answer is applicable to many fruit trees: trees spend energy in order to develop their fruit. For an older tree, there is usually enough energy to grow the tree and develop the fruit. When a young tree produces its first bloom, there is a limited amount of energy. Will all the energy be used to grow leaves and branches or will some be applied to develop fruit? Many citrus growers will choose to sacrifice the first year s crop remove the young developing fruit so their trees will grow quickly and eventually produce more fruit. The rootstock factor There are numerous citrus rootstocks. They impart various different quality characteristics onto the fruit. Some rootstocks will enable the tree to produce an abundance of fruit, but with poor fruit quality (low sugar content). When purchasing a tree, homeowners generally do not have a choice of rootstocks. Commercially, it is an important factor when selecting new trees to plant in an orchard. On the other hand, if the first fruit is left until maturity, that fruit is using energy at the expense of the growth of leaves and branches. Since the resulting differences in yields are generally small, my advice for the homeowner, is to enjoy the first season and let the fruit set! 4

17 Citrus Dry, Flavorless Citrus? Overly mature fruit is a leading cause of dryness in citrus. In other words, if the fruit is left on the tree too long, drying occurs. A few other reasons include: 1. The application of too much nitrogen. 2. At times, dryness may occur when a tree is young; the fruit will improve as the tree ages. 3. Trees budded on certain vigorous rootstocks will make the problem of dry fruit worse. 4. For citrus grown in subtropical climates, dry fruit can be the result of freezing temperatures. Overall, certain varieties of citrus, especially mandarins, seem to be more susceptible to producing dry fruit. In Hawai`i and other tropical areas, a further complication is the fact that citrus fruit does not color well. In other climates, such as California, fruit develops a deep orange color due to the great differences between day time and night time temperatures. Under these conditions, oranges may actually turn color before they are sweet enough to pick. In the tropics, however, where there are less temperature fluctuations, the orange coloration does not develop well and, therefore, is not a good indication of ripeness. In fact, fruit that is sweet will frequently show green coloration. By the time it develops good color, it may have dry segments already forming. If you don t know the harvest season for your particular fruit, I would suggest picking one good sized fruit, even though it may still be greenish in color. If it is not sweet enough, pick one every 1-3 weeks until it tastes sweet. Fruit will develop more sugar the longer it is held on the tree. 5

18 1 Plants Citrus Scab Disease What causes the scabby bumps on citrus fruit? This disorder, common in high rainfall areas is called citrus scab. The disease occurs here, as well as in Florida, but not in California due to the dry climate. It is caused by a fungus, Elsinoe fawcetti, and affects a wide range of citrus. The light brown, raised, warty scabs appear on young stems, leaves and fruit. Leaves develop some resistance to citrus scab with age. The scabs consist of the body of the fungus plus the swollen tissue of the host plant. Spores are produced within these scabs and will spread to other tissues by the splashing rain or irrigation water. After 3 or 4 hours under wet conditions, the spores germinate and infect new tissue. Control Select a resistant species or variety. Plant in as sunny and dry location as is available. Intercrop citrus with non-citrus plants or resistant citrus trees. Citrus scab can reduce yield and will certainly reduce quality of the fruit. However, for home production, as bad as it looks, the fruit can still be sweet and juicy. For those caring about the external appearance of the fruit, trees can be sprayed with a copper fungicide. Yet even numerous applications may not be effective due to high rainfall. Highly susceptible citrus types: Fremont, Clementine, Murcott and Frost Satsuma mandarins; Orland Tangelo; Tahitian lime and Rangpur lime. Not susceptible or immune citrus types: Sweet orange, navel orange, pummelo and grapefruit. 6

19 Citrus Citrus Gummosis Why do citrus trees have, in general, an unhealthy appearance? Some citrus trees look unhealthy because of a common fungal disease called gummosis. Such trees are sparsely foliated with twig dieback. Trees become infected when fungal spores on the ground splash onto the trunk. If the trunk remains wet for many hours, whether from rain droplets or irrigation, infection takes place. The fungus attacks and kills the bark but will not penetrate into the wood. If these lesions are discovered early, the fungus can be stopped, and the tree saved. But once the infection spreads and kills more than a third of the bark tissue around the trunk, the tree will either die or produce poorly. We hope that you have enjoyed what you have read thus far and would like to continue on and read more. You can follow the link below to purchase Ask the Garden Guy. We also hope you share this book sample with your friends. 7