South African Daisy

The South African daisy is a popular cultivated plant. In recent years it has been planted widely in gardens, in soft areas along roads and in other public places so I was not too surprised when I saw it growing profusely along the side of several country roads near Rabat.

This species of daisy can grow up to half a metre high. Many varieties are available in garden centres throughout the world and new ones are being created every year.

The South African daisy is one of several species of related daisies originating in southern Africa. It is usually found in high altitudes being most adapted to live between 1000 and 3000 metres above sea level.

Plants can be annuals or perennials. In areas where the ground freezes they survive the colder parts of the year as seeds but in milder climates they can live for several years.

The flowers have a typical daisy shape. In wild plants they are pink with a yellow disc with a blue centre.  Cultivated varieties have large flowers which range in colour from white to violet.  Some varieties have spoon-shaped petals.

In Malta the South African daisy readily propagates from seed and it can easily spread into the Maltese countryside. Introduced species can spread very fast because and outnumber indigenous species.

In fact the most common plant in the Maltese countryside, the Cape sorrel, known in Maltese as ħaxixa ngliża is also a native of South Africa. It was introduced in Malta about two hundred years ago as a garden plant but soon escaped into the countryside and spread throughout the Maltese islands. It is now found in most Mediterranean countries.  

This article was published in Th Times of Malta on 20 March 2014

Otala punctata

Otala punctata

Otala punctata is the scientific name of a snail indigenous in Spain but which a few years ago was discovered in the Maltese islands.

It does not seem to have an established name in English. In Spanish it is called la cabrilla which according to an online translator means the leopard. In a database it was referred to as the Spanish snail so for this article to avoid constantly using its scientific name I decided to call it the Spanish leopard. It has not yet been given a Maltese name.

This species can be found in eastern Spain, the Balearic Islands, Corsica, the south of France and northwestern Algeria. Nowadays it can also be found in the Americas including the United States, Argentina, Uruguay and Chile. In the United States it is being assumed that it could be a serious pest which could have negative effects on agriculture, and local biodiversity. In Europe it has been found also in Sardinia.

It appeared in Malta around 2003. It established itself in the areas surrounding a plant nursery in Mosta which indicates that it was probably imported accidentally with plants. Studies have shown that its range expanded slowly into the surrounding areas.

It was recently recorded in fields around Baħrija. No Spanish leopards were recorded between Baħrija and Mosta. This indicates that the snails in Baħrija were introduced there by humans. Although it is possible that this was an accidental introduction it could also have been introduced intentionally.

If this did happen it was a very irresponsible act as the introduction could have many negative consequences for the area.

Introduced species often do not have natural enemies and often increase in numbers to the detriment of local species. The Spanish leopard is very similar to the indigenous common garden snail, the species that is collected for cooking and could interact negatively with it.

It could also become a serious pest, creating more problems to the farmers of the area. This could lead to the use of even more snail poison with more negative consequences to the environment.

In Spain this species is cooked in a spicy tomato sauce and no harm would be done if it is also collected in Malta for consumption. 

 

The geranium bronze

Geranium bronze, Cacyreus marshalli,

The geranium bronze is a recent addition to the butterflies of the Maltese islands. It is native to South Africa where it feeds on wild pelargonium geraniums (sardinell in Maltese) which also originate in South Africa. This species is often is often considered a pest because of the damage it causes to the cultivated pelargonium.

The South African butterfly was first recorded in the Balearic Islands in about 1987. It was feeding on cultivated pelargonium geraniums. From there it was introduced to Spain, France and Portugal. In 1997 it arrived in the UK. In Malta it was recorded for the first time in spring 2007.

Once it arrived in Europe it spread quickly in Mediterranean countries mainly because of the popularity of its food plant as well as because parts of South Africa have a Mediterranean climate. It thus found the right conditions to survive and expand its range.

At present it is restricted mainly to Mediterranean Europe but its range might expand further north as is happening with other species. Studies have shown that as a result of global warming and climate change, the range of several species of butterflies is moving north. At the same time some species are disappearing from their former range as the climate becomes too warm for them.

As butterflies disappear in one area new species appear in areas where they had not been recorded before. It is assumed that this is also happening with other insects such as moths, flies and bees, which are not as easy to record and monitor as butterflies.

On continental land masses this is a continuous process but on islands such as Malta insects might disappear because of these changes but new ones are added more slowly as potential invaders might find it difficult to cross the sea separating the Maltese islands from North Africa. 

The moonflower – an alien species

The moonflower is another alien species that first came to Malta as a cultivated garden plant and which is now thriving in the Maltese countryside. Although it is not as common as some other alien species such as the ubiquitous Cape sorrel (ħaxixa ngliża), when present, it is very noticeable because of its large leaves and white or pink flowers.

The flowers of the moonflower open at night and close early in the morning. Their light colour, large size and fragrance make it easier for the flowers to be seen in the dark especially by moths particularly the hawk moths.

The moonflower is a native of the tropical and sub-tropical parts of the American continent. It can be found all the way from northern Argentina to Mexico and Florida.

In Malta this species usually flowers between March and July but in gardens, where it is watered in summer, and in humid valley bottoms it can continue blooming until much later.

This plant is rich in sulfur, an element which is still used in vulcanisation of rubber, a process discovered by Charles Goodyear in 1839 but in southern America, the natives had been using the moonflower to vulcanise the latex of two plants to make bouncing rubber balls 3,000 years before him.

The moon flower belongs to the convolvulus or bindweed family the group in which we find many species of bindweeds which are known in Maltese as leblieb as well as the morning glories. It is in fact it is most closely related to the garden morning glory, the popular garden plant. 

A number of closely related species are used as food while others are used medicinally. Others contain psychoactive substances which were used in religious and spiritual ceremonies to induce an altered mental state similar to that from modern drugs such as LSD, opium and some mushrooms. 

This article was published in The Times on 14.09.11

Lantana

Lantana (Lantana camara)

In Malta the lantana grows very well and although it is widely planted as an ornamental garden plant it has not become a pest as it has in many tropical and sub-tropical countries.

 It is originally native of the American tropics. Its native range includes Mexico, Colombia and Venezuela as well as in the state of Texas in the United States.

 In Malta it is commonly known both in English and Maltese as lantana but it is also known as the Spanish flag, West Indian lantana and the red or yellow sage and in some places as ham ‘n eggs or bacon and eggs. The latter two names are popular in the United States because of the yellow and pink inflorescence.

In countries with a climate similar to that of its country of origin it can become a serious pest can push out native vegetation. It has invaded many parts of India, Australia and Africa. A farmer in Zimbabwe whom I was visiting many years ago had to use tractors to pull out the large lantana bushes that had taken over some of his fields.

The plant is slightly toxic and animals can become ill after eating it. Its berries are edible although they are toxic when still green.

A plus point for this species is that it’s flowers attracts many butterflies, moths and bees. In the United States it is often planted in butterfly gardens. I often spend a long time taking pictures of insects visiting the flowers of a lantana hedge at Buskett Gardens.

In parts of India the stalks of the lantana are now being used to make household furniture while the smaller branches are tied together to make brooms. Lantana is also used in herbal medicine. Leaf extracts are said to have antimicrobial, fungicidal and insecticidal properties. 

This article was published in The Times on 13.12.10

The prickly pear

The prickly pear

The prickly pear tree is often planted around fields in Malta and Gozo as a windbreak and for its fruit.

 Like all cacti it is a native of the American continent and did not arrive in Europe before the discovery of this continent.

 This species is believed to be the earliest species of cactus to be cultivated and nowadays many hybrids and varieties exist. Its exact origins are not known but it probably came from Mexico where similar species can still be found growing wild.

It is nowadays cultivated in many arid and semiarid regions of the world, especially around the southern and eastern coast of the Mediterranean. In Mexico it is also grown for the young leaf-like stems which form part of many traditional Mexican recipes.

Prickly pear is known in Maltese as bajtar tax-xewk. Several varieties can be found in Malta each of which has a distinctive name. The three most common varieties are the “yellow’ variety is known as isfar or Malti, the ‘red’ known as as l-aħmar or l-ingliż and the ‘white’ known as abjad or Franċiż.

 Other less common varieties include tax-xitwa which ripens between October and December, l-Ispanjol which has large reddish fruit, and the lanġasi which has pear-shaped fruit.

It is widely believed that prickly pears have medicinal properties. Many chemical compounds have been extracted from it which have been found to be useful against several conditions especially inflammations. In Malta it was used mainly against stomach aches, bone pain, inflammations, and insect stings. 

It is nowadays being used in cosmetics and in food supplements. The fruit is also used to make jams, jellies and liqueurs. The local bajtra is one while Tungi Spirit which is produced on the island of Saint Helena is another.

 The Mexicans have been using prickly spears to produce a spirit known as colonche for thousands of years.

A species of scale insect thrives on the prickly pear. 

This insect produces carmic acid which is used to make cochineal, a red dye used in red food colouring and cosmetics. The dye was used by the Aztec and Mayans in Oaxaca, Mexico, and exported to Europe. In the mid 19th century an attempt was made to grow these insects on Maltese prickly pears and start producing cochineal in Malta but the project never took off the ground and was abandoned after some years. 

This article was published in The Times on 07.09.2010

The destructive red palm weevil

The red palm weevil has been in the news since it appeared in Malta about three and a half years ago. It is a large rusty-red beetle that lives on palm trees and can kill the host plant. It is a strong flier. 

Last week one flew through my bedroom window in a locality where there are no palm trees within a radius of several hundred metres.

The red palm weevil, which has been given the Maltese name bumunqar aħmar tal-palm, came from tropical Asia from where it spread to Africa and Europe. It reached the Mediterranean in the 1980s and was first recorded in Spain in 1994. In 2006 it was found in France and in 2007 it was recorded from Malta.
The adult weevil damages palm trees through feeding but it is the larva that kills it by burrowing into the trunk.

The cause of the high rate of spread of this pest is human intervention, by transporting infested young or adult date palm trees and offshoots from contaminated to uninfected areas.

Information on Red Palm Weevil was first published in 1891 in India. This pest was first described as a serious pest of the coconut palm in 1906, while in 1917 it was described as a serious pest in the date palm in the Punjab, India.

It is considered as the most serious pest of palm trees in the world. Control is mainly through the use of pesticides although other measures such as attracting the adult insect into traps by means of pheromones are sometimes used. Pheromones are chemicals released by females to attract males.

It has been found that the most effective way to apply pesticides directly into the trees by injecting it directly into the trunk. As happens whenever pesticides are used there can be serious negative consequences to the environment. 

These chemicals leach into the soil and water killing other organisms. In other countries experiments are being carried out to assess the effectiveness of biological methods of control.

One such method is by the use of nematodes that attack the insect killing it within three days but what is effective in the laboratory does not necessarily work in nature.

This is not the only pest that arrived in Malta in the past few years. Another pest which has had serious negative consequences is the tomato leaf miner which last summer destroyed a large percentage of the tomato crop.

This article appeared in The Times 17.03.2010