The Plant Destroyer

 

The plant pathogen genus Phytophthora, a water mold with similarities to a fungus, is a worldwide threat to ornamental and commercially valuable plants due to how it can develop undetected in the early stages of an infestation. While there are some species of Phytophthora that begin an infestation on the above ground portion of a plant, a much larger portion of the approximately 170 known species of the pathogen start out destroying a plant from within its roots. Phytophthora moves upward from the roots through the water channels of the plant, interfering with the plant’s ability to absorb water as it goes. The effect makes the plant appear drought-stricken, which is essentially the case.

 

One of the plants heavily afflicted by Phytophthora in the past 30 plus years has been the cocoa tree, Theobroma cacao, and specifically the cocoa trees planted in western Africa, where most of the world’s cocoa beans are produced. The species of Phytophthora doing the most damage in that period has been Phytophthora megakarya, a disease that blackens the pods which contain the cocoa beans, rendering most of them unfit for consumption. This disease and a virus transmitted by mealybugs called cacao swollen shoot virus (CSSV) in combination have decimated cocoa tree plantations in western Africa in recent decades.

Plant Disease Triangle
A Venn diagram showing the combination necessary for disease to form. This can apply to humans and animals as well as to plants. Illustration by Earlycj5.

Phytophthora megakarya was introduced from the Americas, where it had long co-existed with the native cocoa trees. The cultivated cocoa trees of western Africa had developed for generations without having to cope with infestations from megakarya, though they had long been contending with Phytophthora palmivora, a less devastating disease for them.

CSSV was native to the forest trees of western Africa, where it did little damage because of long term co-evolution of the trees with the virus. The introduced cocoa trees had no inherited defense against CSSV, resulting in afflicted cocoa trees losing vigor and dying within a few years. Meanwhile, the ants that farmed the mealybugs for their sugary secretions have ensured they continue to live safe from predators by guarding them, even building shelters for them.

Chocolate has grown steadily more expensive, at a rate beyond ordinary inflation, due primarily to shortages of cocoa beans caused by these pathogens. Another reason for chocolate price increases has been related to the salutary shift away from indentured labor on cocoa plantations, making the price more accurately reflect the true cost of production. The cost of production is bound to catch up with any resource as nature asserts itself in one way or another, or in many ways, and imagining that we are immune or insulated from the effects of that assertion is mere hubris and folly. Ultimately, we will pay the price.
— Izzy

 

Daffodilly March

 

In most of the country, daffodils (genus Narcissus) bloom in March and are among the first signs of spring. Some places might have blooms as early as February, and others not until April. In all places, the leaves pop up from the ground while freezing weather is still frequent, and inexperienced gardeners and curious onlookers worry that the plants have come up too early and will suffer damage from the cold. Not to worry. The daffodils have been through it all before and will be fine. Any damage they do incur from late winter weather usually comes from being bent down to the ground or snapped by the weight of a late snow or ice storm.

 

Deer, rabbits, and squirrels do not eat daffodil bulbs, foliage, or flowers since they are toxic. The plants spread by jumping from place to place by seed dispersal as well as increasing into clumps formed by daughter bulbs dividing from their parent bulbs, rather like offspring who have matured and set up housekeeping next door. Not all daffodils are noticeably fragrant, and as often happens with flowers it is the older, original varieties that are most fragrant, because plant hybridizers sometimes lose that aspect in pursuit of other traits such as size or color. Trade-offs.

Narcissus poeticus
Narcissus poeticus. Photo by Jean-Jacques MILAN.

Despite a substantial list of pests, fungi, and viruses that can adversely affect daffodils, in practice they should not gravely concern the gardener since the daffodils seem to cope well on their own. The worst condition affecting daffodils, particularly their bulbs, comes from poor drainage or excessive water, particularly in winter. Hardly anyone likes cold, wet feet, and daffodils are no exception. On account of the wet winter in most of the eastern half of the United States, daffodil displays may be subdued this March.

In the 1965 film Doctor Zhivago, a long winter finally turns to spring, heralded by a field of daffodils.

About the only thing an American gardener can say against daffodils is that they are not native to North America or to any part of the Western Hemisphere. Daffodils originate from southern Europe and northern Africa. That daffodils are not native here is an academic complaint, however, since the genie can hardly be stuffed back in the bottle at this point. Most of the people living now in the Western Hemisphere do not belong here, either, and it’s possible to argue they have done far more damage to the native habitat than anything innocent daffodils could have done. On the contrary, daffodils perform a great service everywhere because their trouble free disposition, loosening of hard soils, and cheerful announcement of spring give a greater portion to the gardener and non-gardener alike than they require in return.
— Izzy