Coconut pests and diseases.pdf

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Part of The Coconut Journal

extracted text: Ccccnlt Pests And Diseases By F. Q. OTANES Asst. Chief, Plant Pest and Disease Control Division Bureau of Plant Industry ALTHOUGH the coconut palm is considered a herby plant and grows or thrives in differ ent types of location, yet, like certain other palms, it has one great disadvantage in that nor mally it has only one growing point. Once this growing point (the cabbage or “ubod”) is vitally hurt, the plant succumbs. This fact is important to bear in mind in the control of coconut pests and diseases some of which, unfortunately, attack this vital part—the cabbage or “ubod”. The maladies that damage this vital part of coconuts are the black beetle or “uang” and the so-called coconut bud rot disease. There are several others, however, that attack other parts of the plant to such an extent that its vitality may be impaired temporarily for several years or permanently as to cause it to be unproductive or sterile as to be practically useless. Among these are the coconut leaf miner, scale in Different stages of the black beetle or "Uang” Oryctes rhinoceros. (Courtesy Dept, of Agri. & Com.) sects, slug caterpillars and stem bleeding disease of coconut and the so-called “cadang-cadang” disease. The Black or Rhinoceros Beetle or “Uang” and Red Beetle This insect is so common that every coconut planter is familiar with it. Its body is horny and has strong jaws or mandibles and legs and strong projection on top of its head which enable it to dig into piles of decaying organic matter where it lays its eggs or tearing its way into the crown of coconut where it feeds. The favorite breeding places or media of tkvis. beetle are dead coconut trunks, compost, manure and sawdust piles. Hundreds, nay thousands, of the grubs are often encountered in such places. In lo calities where these media abound, many coconut trees often suffer from serious injury and later suc cumb. The life cycle of this insect is estimated to be about a year. Control The first requisite in the control of this pest, therefore, is cleanliness in coconut groves. In or der to protect coconut trees, the Government, through the Bureau of Plant Industry, has promul gated an administrative order by which all parties concerned can be compelled to keep their premises and coconut groves free of all decaying organic matter in order to prevent the breeding of the in sect. Sawdust piles in particular breed countless numbers of grubs and, therefore, sawmill owners can be compelled to dispose of their sawdust piles. It is only by keeping the coconut groves clean that it pays to get after the beetles that are in the trees. These can be collected from the trees with hooked wires or rods and traps. One way of trap ping the beetles is to construct rectangular pits in in the groves. Compost, pieces of coconut trunks, etc., are put into the pits and these are provided with covers with slits in the middle which will al low the beetles to get into the pits but will prevent their getting out. Such traps should be examined now and then so that the insects caught therein may be destroyed. The Red or Asiatic Palm Weevil Another destructive beetle — a weevil — is the so-called red or Asiatic palm weevil, known in science as Rhynchophorus ferrugineus. The insects lay their eggs in the trunks of the trees, especially in injured portions of coconut trees, and the re sulting larvae or grubs may tunnel their way into the young or growing portion of the coconut. Trees attacked by the grubs usually succumb. To prevent attack by this beetle, coconut trees should not be injured in any way. Where the beetles are prevalent, the practice of making cuts on the coconut trunks should be stopped as this predisposes the trees to attack. Trees in which larvae are presPAGE 3 THE COCONUT JOURNAL ent may be treated with carbon bisulphide to kill the insects. The chemical may be injected into the trees by means of syringes. The beetles may also be trapped as in the case of the black beetles. The Coconut Leaf Miner Because of its extensive ravages in Laguna, Tayabas and Batangas during 1929, 1930 and 1931, no other insect of the coconut has received as much publicity as the coconut leaf miner, known in science as Promecotheca cumingi. The insect is a yellow ish brown beetle of the size of a firefly. The in sects lays its eggs in the coconut leaflets and these hatch into footless, flattish and whitish larvae which feed within the leaves causing blotches or mines; hence the name of the pest. ¡jThe adult beetles feed on the surfaces of the leaves. If the beetles and their larvae are abundant their combined attack cause the rapid drying up of the coconut leaves and the trees may not bear any fruits for one or two years. The methods of control employed under the Bu reau of Plant Industry and which are recommended to coconut planters are as follows: 1. Systematic cutting off of the infested leaves under close and expert supervision in order to des troy the larvae and pupae. 2. Collecting the beetles. 3. Spraying infested trees and those around them with soap solution and lead arsenate to des troy the adults. 4. Rearing and liberation of the parasites that attack the eggs, larvae and pupae. Scale Insects There are several scale insects that have been observed rather harmful to coconuts. One of these is the Florida red scale. The insects suck the juice of the leaves. In some places, they often become abundant and cause the drying up of the leaves of many trees. Closely allied to the red scales are mealy bugs and white flies. These also suck the juices from the leaves. These are quite common and destruc tive in certain provinces. Control The chief method of control against these in sects is periodical spraying with soap solution or oil emulsion. Cutting of the badly infested leaves also helps. Under proper technical supervision, the rearing and liberation of the parasites that attack the insects may be undertaken as has been done and is being done in other countries. Caterpillars There are at least four kinds of caterpillars that at times become abundant as to cause consi derable destructions. Two of these are two kinds of caterpillars, known as slug caterpillars, because they resemble slugs in shape and in habits—being slow moving. These are green in color about 2y2 centi meters long when full grown and with spines, which when touched, cause skin irritation. The other two caterpillars are the young of certain moths known PAGE 4 as skippers. These are light greenish or whitish caterpillars which fold the coconut leaves. Control 1. Spraying with soap solution either with lead arsenate or derris. 2. Collecting the caterpillars and pupae. 3. Encouragement of insectivorous birds in the plantation. 4. Rearing and liberation of insects that are parasitic and predatory on the eggs, caterpillars and pupae. Oriental Migratory Locust The Oriental Migratory Locust is not a regular pest of coconuts. However, whenever there is an outbreak coconut groves, especially those along the paths of invasion, often suffer from the attack. The defoliated coconuts may not bear any fruits for one or two years. The migratory locust is known to breed into enormous swarms chiefly in the out-of-the-way places, that is in the vast isolated grasslands, es pecially in Mindanao. Outbreaks of this pest oc cur at intervals of ten or eleven years and each outbreak usually lasts for several or many years, depending upon natural factors and the campaigns waged against the pest. Between outbreaks (that is when there are no migratory swarms in cultivated and populated areas), the insects are known to live as solitary lo custs, like ordinary grasshoppers. When certain un usual conditions of climate obtain, such as drought conditions, these solitary locusts are known to come together in certain areas and their getting together apparently stimulate their mating instinct and they Coconut trees des troyed by both black beetle and leaf min ers. (Courteay Dept, of Agri. & Com merce} NOVEMBER, 1941 produce small or loose swarms called transiens. Where conditions appear to be most favorable for their multiplication, these small swarms go on in creasing into huge migratory swarms, which invade the cultivated and populated areas. Such swarms persist for sometime, the length of the period of their existence depending on natural factors, such as those of weather, natural enemies and the cam paigns waged against the insects. When their num bers are greatly reduced, those that are left sooner or later produce progeny consisting of solitary forms that live and behave like ordinary grasshoppers. Such solitary forms look so different from the mi gratory that they were previously considered as a distinct species, when in reality they constitute merely a phase of the same species to which the mi gratory forms also belong. Control Measures 1. Catching the flyers with nets and coralling the hoppers into pits. These methods are effective, especially in more or less well populated provinces and where the people comply strictly with the pro visions of the Locust Act (Act No. 2472). 2. Spraying the hoppers with contact poisons, such as soap solution. 3. Dusting with poison, such as calcium ar senate, derris powder, etc. 4. Application of poisoned bait—such as ba gasse bait. Factors Essential to Locust Control 1. Better compliance on the part of the pro vincial and municipal officials with the provisions of the Locust Act. 2. Wider application of the scientific methods of control, such as the use of various effective poi sons. 3. More financial outlay for the locusts at the sources, that is at their outbreak or breeding places. The locust evil should be combatted at its very roots, so to state. Other Pests of Coconuts Rats cause considerable damage at times to young coconuts. These can best be controlled by the use of poisons such as white arsenic, strychnine, etc., which are mixed with attractive baits, such as boiled rice and fish or grated coconut. Wild pigs, like rats, also cause havoc to young coconuts in many places. These can also be con trolled by certain poisons, like phosphorus com pounds, strychnine, white arsenic, etc. Hunting them will also help minimize damage. Fencing is resorted to in some places. Large fruit bats are at times harmful in some places by eating the young fruits. The most effect ive way of controlling these is by shooting them in their roosting places during the day time. Poi soning against these is not considered practical. The use of certain devices to scare away the bats is also practical. Coconut trees show ing leaf miner de vastation. (C o u r t esu Dept. of Agri. & Com.) Bud Rot Disease The most serious disease of coconut is the socalled bud rot disease. It is so called because it attacks the bud causing it to rot. The causal or ganism is known to be a fungus. Control The most effective control for this disease is sanitation and persistent cutting down and thorough burning of the affected parts, for it is known that the disease is infectious. Proper cultural measures should be practised so as to increase the vigor of the trees. Spraying the healthy trees around infected ones with Bordeaux mixture may also be practised as a preventive measure. The control of insects, such as black beetles, will also help minimize, if not prevent the dissemination of the disease. Cadang-Cadang Disease This disease manifests itself in the general yel lowing and stunting of the growth of the trees. It is known to be chiefly a physiological disease ow ing to water-logging, malnutrition, etc. The chief remedies are proper drainage and application of fertilizers or green manuring. Concluding Remarks In the control of pests and diseases of coco nuts the preventive and cultural measures should be given due attention. Remedial measures are, of course, effective but because of the size of the trees such measures may entail considerable expenses. They should be timely and properly applied and un der expert advice at first. All coconut planters should co-operate especially with the Government (Please turn to page 21) PAGE 5 NOVEMBER, 1941 COCONUT PESTS AND... (Continued from page 5) in its efforts to prevent the spread of such maladies as leaf miner, locusts, black beetles, scale insects and bud rot, which may vitally affect the coconut industry if they occur as epidemics. This is bound to occur if planters in particular slacken in their joint efforts to stamp them out while still greatly localized. In no other phase of agriculture is cooperation more greatly needed than in the control of plant pests and diseases. The efforts of any individual planter in controlling beetles, bud rot and the like in his grove may not be of much avail if his neigh bors neglect the infestations and infections in their own groves. Slug caterpillars attacking coconut leaves. (Courtesy Dept, of Agri. & Com.) The General Manager, National Coconut Corporation Manila. Dear sir: I write to seek information with regards to the cur rent price of buri-braids as paid by your Corporation. I am of the information that at present you are paying a good price for such merchandise. For this reason, I beg to ask you the prices for the different kinds of braids, and if possible to furnish me with the detailed list of them all and the dates of good prices. As the braid industry here is our important source of livelihood, I am requesting you for their exact prices as you buy them together with the quantity you need in case we intend to send them to you directly. Thanking you in advance and hoping for your kind attention and reply, I remain, Very respectfully yours, Antonio M. Rose In reply to your letter, please be informed that we are in the market for the following buri braids; 1. Apatan-Khaki 20 mm. wide and 60 yards long @ P.28 per roll-already pressed and packed. 2. Siyaman-Khaki 18-to 20 mm. wide and 60 yards long @ P.45 per roll-already pressed and packed. As we will need about 10,000 rolls of each type men tioned above, please let us know as soon as possible if you could supply us these braids ad the prices quoted and also indicate how many rolls you can supply in one month. The National Coconut Corporation Manila. Dear sirs: In your “Coconut Journal” of April, 1941, my at tention was called in the article MAKE YOUR OWN SOAP AT HOME THE NACOCO WAY. Since then I have tried to buy Nacoco Sosa and Nacoco Langis Ng Niyog (beer bottle size) but sorry to inform you that I cannot find any in the market. In this connection, I hereby respectfully request that I be furnished with the names of persons or stores from where I can be able to buy the above mentioned articles. Furthermore, I want to inform you that I want to try the SIMPLE METHOD of soap making you have published in that Journal, which interested me more. Very respectfully yours, (Mrs.) Mercedes Pagtalunan We are selling Nacoco Sosa right in our office. You may buy your coconut oil from Chinese stores or direct from oil manufacturers like, Spencer Kelloff & Sons, Philippine Refining Co. and Luzon Industrial Corporation. PAGE 21
Date: 1941
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