Peach Tree Diseases: MCQ Diseases of Peach

Yesterday I posted MCQs on Pear diseases. Today I am posting MCQs on Peach disesases.

Q 1 Peach leaf curl is caused by.

a. Taphrina deformans	c. Taphrina maculans
b. Stigminia carpophila	d. Phyllosticta persicae

Q 2 Peach scab is caused by

a. Venturia inaequalis	c. Venturia pirina
b. Venturia carpophila	d. Spilocaea pomi

Q 3 Vector for peach X disease is  

a. Psylla	c. Leaf hopper
b. Green peach aphid	d. Peach leaf curl aphid

Q 4 Vector for peach  mosaic virus is

a. Green peach aphid	c. Eriophyid mite
b. Peach leaf curl aphid	d. Psylla

Q 5 Primary source of inoculum for peach scab is

a. ascospores produced in cleistothecium	c. dormant mycelia in fallen leaves
b. Spilocea type of air borne conidia	d. Rain water splash and air borne conidia

Q 6 Stigminia blight is also known as

a. Peach blight	c. California peach blight
b. New castle peach blight	d. Target leaf spot

Q 7 Primary source of inoculum for peach rust is

a. Teliospore	c. Urediospores
b. Basidiospores	d. Aceiospores

Q 8 Biological control agent for powdery mildew of peach

a. Erwinia herbicola	c. Ampelomyces quisqualis
b. Pseudomonas fluorescens	d. All of these

Q 9 Fruiting body produced by Ampelomyces quisqualis is known as

a. Pycnidium	c. Cleistothecium
b. Apothecium	d. Pseudotheium

Q 10 Chemicals for control of powdery mildew

a. Elemental sulfur	c. Wettable Sulfur
b. Hexaconazole	d. all of these

You may answer these questions in comment section. I shall be posting answers for these questions tomorrow in comment section.

Multiple choice questions on pear diseases

Yesterday I finished objective questions on apple. Today I am posting MCQs on pear diseases. I hope this will help you in preparing for your examination

Q 1 Pear scab is caused by.

a. Podospharea leucotricha	c. Gymnosporangium libocedri
b. Fabraea maculata	d. Venturia pirina

Q 2 Sexual spores of Pear scab develop in

a. Pseudothecia on infected fallen leaves	c. Perithecia on infected fallen leaves
b. Cleistothecia on infected fallen leaves	d. Apothecia on infected fallen leaves

Q 3 Vector for pear decline disease is  

a. Pear psylla	c. Pear aphid
b. Green peach aphid	d. Woolly Apple Aphid

Q 4 Sexual fruiting body of powdery mildew causing fungi is

a. Peritheicium	c. Cleistothecium
b. Apothecium	d. Pseudotheium

Q 5 Primary source of inoculum for powdery mildew of pear is

a. ascospores borne in cleistothecium	c. dormant mycelia in infected buds
b. barrel shaped conidia	d. superficial mycelia on infected buds

Q 6 Erwinia amylovora overwinters in

a. natural openings or woulds	c. Nectrathodes
b. bark tissues along edges of cankers	d. Venturia pirina

Q 7 Primary source of inoculum for pacific coast pear rust is

a. Telial galls on cedar plants	c. Uredia on flowering pear (Pyrus calleryana)
b. Urediospores	d. Aceiospores

Q 8 Biological control agent for powdery mildew of pear is

a. Erwinia herbicola	c. Ampelomyces quisqualis
b. Pseudomonas fluorescens	d. All of these

Q 9 Fruiting body produced by Ampelomyces quisqualis is

a. Pycnidium	c. Cleistothecium
b. Apothecium	d. Pseudotheium

Q 10 Fire blight can be managed by  

a. pruning diseases parts	c. Using COC or Streptocycline
b. controlling insect vectors	d. all of these

Answer these questions in comment section. I shall be posting the answers tomorrow in the comment section.

Apple Tree Diseases: Objective questions on apple

Yesterday I posted some objective questions on apple in the form of fill in the blanks. Today again I am going to post some more fill in the blanks with reasoning questions. This will complete important questions from apple fruit crop.

Fill in the blanks:

1. Unlike apple scab fungus, the spores of powdery mildew do not require _____________ for germination.
2. Black rot disease of apple is caused by                               and is also known as                         .
3. Phytophthora cactorum  survives in the soil as                                      that are resistant to drought and relatively resistant to chemical treatment.
4. Characteristic feature of white root rot is                                                that can be seen on roots during monsoon months and can be seen on soil level.
5. Young trees if infested with                                                   may die quickly with necrotic leaves still on the dead plant is a characteristic symptom.
6. Soil pH                 , soil moisture                 and Temperature                  play an important role in incidence and survival of Dematophora necatrix.
7. Crown gall of apple is caused by                                 and hairy root is caused by                       can be managed by bio-control agent                                                   strain

Descriptive questions

1. How excess nitrogen makes the plants more susceptible? What is the role of balanced nutrition in disease management?
2. Why overhead irrigation be avoided during fire blight outbreak?
3. Why control of insects with sucking type of mouth parts is important in management of fire blight of pome fruits?

You may answer the fill in the blanks in comment section. I shall be posting the answers in comment section tomorrow.

Apple Tree Diseases: Objective questions on apple diseases.

Yesterday I started working on objective type questions for the diseases of apple crops. In this series I am going to  post fill in the blanks. Here are few fill in the blanks for apple diseases.

Fill in the blanks

1. Apple scab is caused by _______________ is telomorph, whereas, anamorph of the fungus is ______________.
2. Apple scab disease perinnates in ____________and primary infection is caused by ______________.
3. Leaf __________period and _____________plays important role in primary infection of apple scab.
4. Secondary source of inoculum for scab development is __________.
5. Application of _________to leaf litter during fall (when more than 80% leaves have fallen) hasten decomposition of leaves due to microbial action and reduces primary inoculum.
6. In case of fire blight of apple, tips of young infected shoots wilt, forming a very typical ________________symptom.
7. The fire blight bacteria ____________in bark tissues along the edges of cankers caused by infections during previous years.
8. The Erwinina amylovora penetrate the tree through __________or ______________.
9. Secondary infection of Erwinina amylovora arises from _______of fresh infections.
10. Podosphaera leucotricha overwinters in the ____________that had been infected in the preceding growing season.

You may answer these questions in comment section. I shall be answering these in comment section tomorrow. 

Apple Tree Diseases: Question Bank for Apple Diseases

During the period of lockdown, I thought to help my students in preparation for their exams. Today I am starting with few questions on apple diseases, which may come handy for your exams in near future. Tomorrow I shall be posting some more questions.

MCQ. 

Q 1 The disease which had endangered the very existence of delicious apples.

a. Powdery mildew	c. Fruit spots
b. Apple scab	d. Root rot

Q 2 The breeding of scab resistant varieties of apple was undertaken.

a. IARI	c. RFRS – Mashobra
b. ICAR	d. RFRS – Bikaner

Q 3 The root rot of apple is caused by.

a. Phytophthora cactorum	c. Corticium salmonicolor
b. Podospharea leucotricha	d. Botryosphaeria obtusa

Q 4 Silvering of foliage appears soon after petal fall is the typical symptoms of

a. Nail head canker	c. Pink disease
b. Leaf canker	d. Fruit spots

Q 5 Hairy root is due to.

a. Agrobacterium tumefaciens	c. Podospharea leucotricha
b. Dematophora necatrix	d. Corticium salmonicolor

State True /False

Q 6 The Primary Source of Inoculum  for apple scab is zoospores of pseudothecium.

Q 7 The apple rust is a heterocious & also monocyclic disease.

Q 8 Apple crown rot. Root rot, Collar rot are the complete loss disease caused by a single organism Dematophora necatrix.

Q 9 Apple Dapple /Apple scar skin is a viroid disease.

Q 10 The two crab apples Malus floribunda & Malus toringoides are have resistance against the root rot.

Q 11 Bitter rot, Sour rot, Brown rot are not post harvest diseases.

You may answer these questions in comment box. I shall be posting the answers soon in comment section

Clonal Rootstocks: High Density Plantation

In my previous post on Apple Rootstocks I discussed about advantage of clonal rootstocks. These stocks though have genetic similarity is bound to react similarly to the scion wood. Thus we can visualize the final product and can make a blue print of our production unit. Most of us call horticulture an industry, but how many of us understand that in any of the industry we first calculate the production and then inputs and then we decide about whether to produce or not. Whereas in horticulture as an industry how many of us calculate our production, or visualize the quality or critically decide about critical inputs? Even then this industry is giving us lot of remuneration this means even we are doing horticulture without planning it is giving us the upward growth, what it can do if we plan it properly.

There are number of clonal rootstocks around the world. There are some popular rootstocks like M9, MM106, MM 111, 793, M7, M26, Bud -9, and so on.

M9

World over this rootstock having dwarfing effect is appropriate for dense planting methods. Its use is recommended with the varieties of vigorous development, Fuji, Gala etc. Around the world it has been proven to be the most stable in preciosity, performance and production rootstock with very satisfying tolerance to  Phytophthora disease.  This rootstock requires support for the development of plantation and it is the most widespread and popular rootstock worldwide. Its combination with the varieties of the Red Delicious is not advised.

M26

A very popular rootstock in Greece. It produces trees 65% more vigorous compared to seedling apple tree. It forms the perfect combination with the Red Delicious varieties in every type of orchard planting. It requires careful actions as to accomplish a successful production every year. The quality of the produced product is regarded very nice. Avoid combining it with varieties like Fuji, Gala, Johnagold etc. Along with the variety Granny Smith a good combination is achieved.

MM106

This rootstock is particularly sensitive towards the Phytophthora fungus. It should be avoided in  intensive planting . Its use in moist soil, watered with inclination and in soil which had been previously replanted with apple trees would not be wise. Its products are relatively small so the careful thinning down is demanded. It has a fairly developed rooting system, hence its trees do not require any support.

MM111

This rootstock coordinates very well with the Red Delicious varieties. Its basic characteristic and its advantage over the MM106, is the tolerance towards the soil borne fungus Phytophthora sp. This is the apparent reason why, the use of this rootstock, and not of the MM106, is recommended.

In coming posts I shall be discussing about Planting systems in apple.

Apple Tree Diseases: Monitored Sprays for Apple Scab

This post is in continuation to my previous post on Apple Diseases:Holistic Management of Apple Scab. Here we are going to discuss about Monitored spray control

There are two spray strategies for controlling the diseases i.e. preventive and curative. Since this disease is a polycyclic, the spray schedule should focus on reduction of inoculum and protective covering before the infection takes place based on the predictive models developed at RHRTS Mashobra.

Monitored Spray control:           
 Among two different monitored spray strategies (curative and eradicative) as developed and tried in the orchards, the curative sprays with well timed application of Ergosterol-biosynthesis-inhibiting (EBI) fungicides even after 72 and 96 hour of the predicted infection periods is not only more effective but also economical for control the disease with three lesser sprays.

Av Temp (oC)	Minimum wetness (hr)		Scab appear (days)
	Ascospores	Conidia
17.2-23.8	9.0	5.9	9
13.8-11.0	11.0	7.5	15
10.5-8.5	15.0	9.8	17

The monitored spray programme developed for Indian conditions at Regional Horticultural Research and Training Station, Mashobra, Shimla for the control of spring and summer scab conditions is described below. This strategy is recommended to orchard areas where scab is present.

First Spray:

At green tip stage if scab during last three years was present and temperature after rains remained above 10^oC. The spray strategy to control primary scab must include high residue fungicides for better protective action for longer duration. The strong bio-efficacy of dodine, mancozeb, dithianon, and captan is established on apple parts. The residues of these fungicides are persistent, stable and re-distributive on the foliage and remain effective against primary infection up to 36 days. Hence recommended at green tip stage as first spray under monitored control program in Himachal Pradesh.

Second Spray:

Second spray at pink bud stage is recommended to give protective coverage on plant parts to control primary scab infection during the long flowering session. However, according to monitored spray strategy, this spray is considered to be optional and should be given only if first spray is not given or continuous wet conditions prevailed after the first spray. The fungicides recommended at this stage are both protective as well as curative. However, it is also observed that at high altitude locations (above 6500 ft) where primary infection generally initiates after pink bud stage the first spray at green tip stage is inappropriate. Benzimidazole and EBI fungicides having protective/ curative and broad-spectrum mode of action is recommended for such locations at pink bud stage (as first spray) to control invisible infection caused by apple scab, canker fungi, powdery mildew, core rot and leaf blotch. However, the sensitive flowering stage is avoided for any spray as might obstruct the cross-pollination process.

Criteria for sprays:

In addition to its anti-fungal properties it also help in improving fruit set and can be used safely during bloom.

Third Spray:

Third spray at petal fall stage is very essential to protect the newly emerged fruit-lets against primary scab and powdery mildew infections. Moreover, the earlier sprays given either through first spray or at pink bud stage are found ineffective all through the long flowering period of apple. The brands of benzimidazole and EBI are recommended at this stage also having both protective curative and anti-sporulant actions. This group of fungicides is effective to other summer diseases as well and also acts as anti-senescent and increased fruit set.

Fruit Development Spray:

At fruit development stage the actual monitored spray strategy implies where curative fungicide sprays are recommended after the infection period instead of routine sprays. There are three options of sprays and type of fungicides use according to the prevailing weather and scab conditions in the orchards.

Most effective option of curative (EBI) fungicides is to kill the fungus in host tissues after the infection has occurred. However, the fruit development sprays can be extended for longer duration or discontinue in case there is no visible scab on leaves and fruits out of primary infection. This can also be ascertained by the overall scab records in the last three years and no primary symptoms have appeared till date in the current period.

Dormant spray:

Dormant sprays of 5 per cent urea a foliar nitrogenous fertilizer at leaves shedding stage and followed by a spray of Bordeaux mixture (1%) are most effective IDM strategy used to eradicate the most overwintering pathogen/diseases on apples.

In coming posts I shall be discussing about the cankers.